Electrodes for creating lesions in tissue regions at or near a sphincter

ABSTRACT

Improved electrode assemblies for treating a tissue region at or near a sphincter comprise a support structure and an electrode carried by the support structure for advancement in a path to penetrate the tissue region. In one arrangement, the electrode has a non-cylindrical cross section selected to resist deflection when advanced to penetrate the tissue region. In another arrangement, the electrode includes a tissue stop to resist tissue penetration beyond a selected depth. In another arrangement, the electrode includes a proximal portion formed from a first material and a distal tissue penetrating portion formed of a second material different than the first material. The first material can comprise, e.g., stainless steel, and the second material can comprise, e.g., nickel titanium.

RELATED APPLICATION

[0001] This application is a continuation of copending U.S. patentapplication Ser. No. 09/305,270 filed May 4, 1999. This application isalso continuation-in-part of co-pending U.S. patent application Ser. No.09/026,296, filed Feb. 19, 1998, and entitled “Method for TreatingSphincter.”

FIELD OF THE INVENTION

[0002] In a general sense, the invention is directed to systems andmethods for treating interior tissue regions of the body. Morespecifically, the invention is directed to systems and methods fortreating dysfunction in body sphincters and adjoining tissue, e.g., inand around the lower esophageal sphincter and cardia of the stomach.

BACKGROUND OF THE INVENTION

[0003] The gastrointestinal tract, also called the alimentary canal, isa long tube through which food is taken into the body and digested. Thealimentary canal begins at the mouth, and includes the pharynx,esophagus, stomach, small and large intestines, and rectum. In humanbeings, this passage is about 30 feet (9 meters) long.

[0004] Small, ring-like muscles, called sphincters, surround portions ofthe alimentary canal. In a healthy person, these muscles contract ortighten in a coordinated fashion during eating and the ensuing digestiveprocess, to temporarily close off one region of the alimentary canalfrom an other.

[0005] For example, a muscular ring called the lower esophagealsphincter surrounds the opening between the esophagus and the stomach.The lower esophageal sphincter (or LES) is a ring of increased thicknessin the circular, smooth-muscle layer of the esophagus. Normally, thelower esophageal sphincter maintains a high-pressure zone betweenfifteen and thirty mm Hg above intragastric pressures inside thestomach.

[0006] When a person swallows food, muscles of the pharynx push the foodinto the esophagus. The muscles in the esophagus walls respond with awavelike contraction called peristalsis. The lower esophageal sphincterrelaxes before the esophagus contracts, and allows food to pass throughto the stomach. After food passes into the stomach, the lower esophagealsphincter constricts to prevent the contents from regurgitating into theesophagus.

[0007] The stomach muscles churn the food and digestive juices into amass called chyme. Then the muscles squeeze the chyme toward the pyloric(intestinal) end of the stomach by peristaltic waves, which start at thetop of the stomach and move downward. The pyloric sphincter, anotherringlike muscle, surrounds the duodenal opening. The pyloric sphincterkeeps food in the stomach until it is a liquid. The pyloric sphincterthen relaxes and lets some chyme pass into the duodenum.

[0008] Dysfunction of a sphincter in the body can lead to internaldamage or disease, discomfort, or otherwise adversely affect the qualityof life. For example, if the lower esophageal sphincter fails tofunction properly, stomach acid may rise back into the esophagus. Unlikethe stomach, the esophagus has no natural protection against stomachacids. When the stomach contents make contact with the esophagus,heartburn or other disease symptoms, including damage to the esophagus,can occur.

[0009] Gastrointestinal reflux disease (GERD) is a common disorder,characterized by spontaneous relaxation of the lower esophagealsphincter. It has been estimated that approximately two percent of theadult population suffers from GERD. The incidence of GERD increasesmarkedly after the age of 40, and it is not uncommon for patientsexperiencing symptoms to wait years before seeking medical treatment.

[0010] GERD is both a normal physiologic phenomenon that occurs in thegeneral population and a pathophysiologic phenomenon that can result inmild to severe symptoms.

[0011] GERD is believed to be caused by a combination of conditions thatincrease the presence of acid reflux in the esophagus. These conditionsinclude transient LES relaxation, decreased LES resting tone, impairedesophageal clearance, delayed gastric emptying, decreased salivation,and impaired tissue resistance. Since the resting tone of the loweresophageal sphincter is maintained by both myogenic (muscular) andneurogenic (nerve) mechanisms, some believe that aberrant electricalsignals in the lower esophageal sphincter or surrounding region of thestomach (called the cardia) can cause the sphincter to spontaneouslyrelax.

[0012] Lifestyle factors can also cause increased risk of reflux.Smoking, large meals, fatty foods, caffeine, pregnancy, obesity, bodyposition, drugs, hormones, and paraplegia may all exacerbate GERD. Also,hiatal hernia frequently accompanies severe GERD. The hernia mayincrease transient LES relaxation and delay acid clearance due toimpaired esophageal emptying. Thus, hiatal hernias may contribute toprolonged acid exposure time following reflux, resulting in GERDsymptoms and esophageal damage.

[0013] The excessive reflux experienced by patients with GERD overwhelmstheir intrinsic mucosal defense mechanisms, resulting in many symptoms.The most common symptom of GERD is heartburn. Besides the discomfort ofheartburn, reflux results in symptoms of esophageal inflammation, suchas odynophagia (pain on swallowing) and dysphagia (difficultswallowing). The acid reflux may also cause pulmonary symptoms such ascoughing, wheezing, asthma, aspiration pneumonia, and interstitialfibrosis; oral symptoms such as tooth enamel decay, gingivitis,halitosis, and waterbrash; throat symptoms such as a soreness,laryngitis, hoarseness, and a globus sensation; and earache.

[0014] Complications of GERD include esophageal erosion, esophagealulcer, and esophageal stricture; replacement of normal esophagealepithelium with abnormal (Barrett's) epithelium; and pulmonaryaspiration.

[0015] Treatment of GERD includes drug therapy to reduce or blockstomach acid secretions. Still, daily drug therapy does not eliminatethe root cause of the dysfunction.

[0016] Invasive abdominal surgical intervention has also been tried withsuccess. One procedure, called Nissen fundoplication, entails invasive,open abdominal surgery. The surgeon wraps the gastric fundis about thelower esophagus, to, in effect, create a new “valve.” Less invasivelaparoscopic tehniques have also been tried to emulate Nissenfundoplication, also with success. Still, all surgical interventionentails making an incision into the abdomen and carry with it the usualrisks of abdominal surgery.

SUMMARY OF THE INVENTION

[0017] The invention provides improved electrode assemblies for treatinga tissue region at or near a sphincter. The assemblies comprise asupport structure and an electrode carried by the support structure foradvancement in a path to penetrate the tissue region.

[0018] According to one aspect of the invention, the electrode has anon-cylindrical cross section selected to resist deflection whenadvanced to penetrate the tissue region. The non-cylindrical crosssection can vary and be, e.g., rectilinear, oval, or elliptical.

[0019] According to another aspect of the invention, the electrodeincludes a tissue stop to resist tissue penetration beyond a selecteddepth.

[0020] According to another aspect of the invention, the electrodeincludes a proximal portion formed from a first material and a distaltissue penetrating portion formed of a second material different thanthe first material. The first material can comprise, e.g., stainlesssteel, and the second material can comprise, e.g., nickel titanium.

[0021] In one embodiment, the electrode is bent along its axis, e.g., inan antegrade direction or in a retrograde direction. The electrode canbe bent, e.g., in an arc of less than ninety degrees or in an arc ofgreater than ninety degrees. In this arrangement, the relativelyexpensive nickel titanium alloy performs best in the curved regions ofthe electrode, due to its super-elastic properties. The use of lessexpensive stainless steel in the other regions can reduce overall cost,by minimizing the amount of nickel titanium alloy required.

[0022] In one embodiment, a connector couples the electrode to a sourceof radio frequency energy to ohmically heat tissue and create a lesionin the tissue region.

[0023] Features and advantages of the inventions are set forth in thefollowing Description and Drawings, as well as in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0024]FIG. 1 is an anatomic view of the esophagus and stomach;

[0025]FIG. 2 is a diagrammatic view of a system for treating bodysphincters and adjoining tissue regions, which embodies features of theinvention;

[0026]FIG. 3 is a perspective view, with portions broken away, of adevice usable in association with the system shown in FIG. 1 having anoperative element for contacting tissue shown in a collapsed condition;

[0027]FIG. 4 is a perspective view, with portions broken away, of thedevice shown in FIG. 3, with the operative element shown in an expandedcondition;

[0028]FIG. 5 is a perspective view, with portions broken away, of thedevice shown in FIG. 3, with the operative element shown in an expandedcondition and the electrodes extended for use;

[0029]FIG. 6 is an enlarged side view of the operative element whencollapsed, as also shown in FIG. 3;

[0030]FIG. 7 is an enlarged side view of the operative element whenexpanded and with the electrodes extended for use, as also shown in FIG.5;

[0031]FIG. 8 is an enlarged perspective view of an embodiment theoperative element, when fully collapsed;

[0032]FIG. 9 is a side view of the deployment of a flexible endoscopethrough an esophageal introducer into the stomach;

[0033]FIG. 10 is an enlarged view of the endoscope shown in FIG. 9,retroflexed for viewing the cardia and lower esophageal sphincter;

[0034]FIG. 11 is a side view of the deployment of the device shown inFIG. 3 after deployment of the flexible endoscope shown in FIG. 9,placing the operative element in the region of the lower esophagealsphincter;

[0035]FIG. 12 is an enlarged view of the operative element shown in FIG.11, when placed in the region of the lower esophageal sphincter;

[0036]FIG. 13 is an enlarged view of the operative element shown in FIG.11, when expanded into contact with muscosal tissue in the region of thelower esophageal sphincter;

[0037]FIG. 14 is an enlarged view of the operative element shown in FIG.11, when expanded into contact with muscosal tissue in the region of thelower esophageal sphincter and with the electrodes extended to createlesions in the smooth muscle ring of the lower esophageal sphincter;

[0038]FIG. 15 is an enlarged view of the operative element shown in FIG.11, when placed in the region of the cardia;

[0039]FIG. 16 is an enlarged view of the operative element shown in FIG.11, when expanded into contact with muscosal tissue in the cardia;

[0040]FIG. 17 is an enlarged view of the operative element shown in FIG.11, when expanded into contact with muscosal tissue in the cardia andwith the electrodes extended to create lesions in the smooth muscle ofthe cardia;

[0041]FIG. 18 is an enlarged view of the operative element shown in FIG.17, when fully deployed for creating lesions in the cardia;

[0042]FIG. 19 is an enlarged view of the operative element shown in FIG.14 or FIG. 17, after being used to form lesions and in the process ofbeing removed from the targeted tissue site;

[0043]FIG. 20 is a top view of a targeted tissue region in the cardia,showing a desired pattern of lesions;

[0044]FIG. 21 is a perspective view of a “pearshaped” operative elementintended for deployment in the cardia, shown in a collapsed condition;

[0045]FIG. 22 is a perspective view of the “pearshaped” shown in FIG.21, shown in an expanded condition with the electrodes extended for usein an antegrade orientation;

[0046]FIG. 23 is an enlarged view of the operative element shown in FIG.22, when expanded into contact with muscosal tissue in the cardia andwith the electrodes extended to create lesions in the smooth muscle ofthe cardia;

[0047]FIG. 24 is a perspective view of the “pearshaped” shown in FIG.21, shown in an expanded condition with the electrodes extended for usein a retrograde orientation;

[0048]FIG. 25 is an enlarged view of the operative element shown in FIG.24, when expanded into contact with muscosal tissue in the cardia andwith the electrodes extended to create lesions in the smooth muscle ofthe cardia;

[0049]FIG. 26 is an enlarged side view a “diskshaped” operative elementintended for deployment in the cardia, when expanded into contact withmuscosal tissue in the cardia and with the electrodes extended to createlesions in the smooth muscle of the cardia;

[0050]FIGS. 27 and 28 are an enlarged side views operative elementshaving different “peanut” shapes intended for deployment in the cardia,when expanded into contact with muscosal tissue in the cardia and withthe electrodes extended to create lesions in the smooth muscle of thecardia;

[0051]FIG. 29 is an enlarged side view an operative element expandedinto contact with muscosal tissue in the cardia and with “pig-tail”electrodes extended to create lesions in the smooth muscle of thecardia;

[0052]FIG. 30 is a enlarged perspective section view of an electrodehaving a cyindrical cross section;

[0053]FIG. 31 is a enlarged perspective section view of an electrodehaving an elliptical cross section to resist twisting;

[0054]FIG. 32 is a enlarged perspective section view of an electrodehaving a rectilinear cross section to resist twisting;

[0055]FIG. 33 is an enlarged side view of an electrode deployed from anoperative element in the region of the lower esophageal sphincter andhaving a collar to control the depth of tissue penetration;

[0056]FIG. 34 is a side section view of a stationary spine whichcomprises a portion of an operative element and which carries a movableelectrode for creating lesion patterns;

[0057]FIG. 35 is a side section view of a stationary spine whichcomprises a portion of an operative element and which carries a pair ofmovable electrodes for creating lesion patterns;

[0058]FIG. 34 is a side section view of a stationary spine whichcomprises a portion of an operative element and which carries a movableelectrode for creating lesion patterns;

[0059]FIGS. 36 and 37 are enlarged side views of operative elementsdeployed in the cardia and having movable spines for positioning eithermultiple electrodes or a single electrode in different positions forcreating lesion patterns;

[0060]FIG. 38 is an enlarged side view of an operative element thatcarries a steerable electrode for creating lesions in body sphinctersand adjoining tissue;

[0061]FIG. 39 is an enlarged side view of an operative element carryingsurface electrodes for treating abnormal epithelial tissue in thegastrointestinal tract, the operative element being shown in a collapsedcondition and deployed in the region of the lower esophageal sphincter;

[0062]FIG. 40 is an enlarged side view of the operative element shown inFIG. 39 and in an expanded condition contacting the abnormal epithelialtissue for applying ablation energy;

[0063]FIG. 41 is a perspective view of an operative element comprising amechanically expandable basket shown in a collapsed condition;

[0064]FIG. 42 is a perspective view of the operative element shown inFIG. 41, with the operative element shown in an expanded condition toextend the electrodes for use;

[0065]FIG. 43 is a side view showing a spine of the basket shown in FIG.41 as it is mechanically flexed for penetrating tissue;

[0066]FIG. 44 is a side view of another operative element comprising amechanically expandable basket shown in an expanded condition with theelectrodes extended for use shown;

[0067]FIG. 45 is a side view of the operative element shown in FIG. 44in a collapsed condition;

[0068]FIG. 46 is a perspective view of an operative element that isdeployed for use over a flexible endoscope, shown in a collapsedcondition;

[0069]FIG. 47 is a perspective view of the operative element shown inFIG. 48 in an expanded condition and with the electrodes extended foruse;

[0070]FIG. 48 is an enlarged view of the operative element shown in FIG.47, when expanded into contact with muscosal tissue in the cardia andwith the electrodes extended to create lesions in the smooth muscle ofthe cardia;

[0071]FIG. 49 is an end view of the operative element taken generallyalong line 49-49 in FIG. 48, as viewed from the retroflex endoscope overwhich the operative element is deployed for use;

[0072]FIG. 50 is a perspective view of the operative element of the typeshown in FIG. 47, deployed over a flexible endoscope, and including atransparent region within the operative element to permit endoscopicviewing from within the operative element;

[0073]FIG. 51 is a perspective view of the operative element shown inFIG. 50, with the endoscope positioned within the operative element forviewing;

[0074]FIG. 52 is an enlarged view of an operative element comprising amechanically expandable basket deployed over a flexible endoscope andwith the electrodes penetrating the lower esophageal sphinter to createlesions;

[0075]FIG. 53 is a perspective view of an operative element for treatingbody sphincters and adjoining tissue regions, shown in an expandedcondition with eight electrodes extended for use;

[0076]FIG. 54 is a perspective view of an operative element for treatingbody sphincters and adjoining tissue regions, shown in an expandedcondition and four closely spaced electrodes extended for use;

[0077]FIG. 55 a perspective distal facing view of an operative elementfor treating body sphincters and adjoining tissue regions, shown a spinestructure with cooling and aspiration ports located in the spines;

[0078]FIG. 56 a perspective proximal facing view of an operative elementshown in FIG. 56;

[0079]FIG. 57 is a perspective view of a handle for manipulating theoperative element shown in FIGS. 55 and 56;

[0080]FIG. 58A a perspective view of an operative element for treatingbody sphincters and adjoining tissue regions, shown a spine structurewith cooling ports located in the spines and aspiration ports located inan interior lumen;

[0081]FIG. 58B a perspective view of an operative element for treatingbody sphincters and adjoining tissue regions, shown a spine structurewith an underlying expandable balloon structure having pin hole portswhich weep cooling liquid about the electrodes;

[0082]FIG. 59 a perspective view of an operative element for treatingbody sphincters and adjoining tissue regions, shown a spine structurewith cooling ports located in the spines and an aspiration port locatedin its distal tip;

[0083]FIG. 60 a perspective view of the operative element shown in FIG.59, deployed over a guide wire that passes through its distal tip;

[0084]FIG. 61 is a perspective view of a handle for manipulating theoperative element over the guide wire, as shown in FIG. 60;

[0085]FIG. 62 a perspective view of an operative element for treatingbody sphincters and adjoining tissue regions, deployed through anendoscope;

[0086]FIG. 63 is a perspective view of an extruded tube that, uponfurther processing, will form an expandable basket structure;

[0087]FIG. 64 is a perspective view of the extruded tube shown in FIG.62 with slits formed to create an expandable basket structure;

[0088]FIG. 65 is the expandable basket structure formed after slittingthe tube shown in FIG. 63;

[0089]FIG. 66 is a side section view of the esophagus, showing the foldsof mucosal tissue;

[0090]FIG. 67 is a perspective view of a device for treating bodysphincters and adjoining tissue regions, which applies a vacuum tomucosal tissue to stabilize and present the tissue for the deployment ofelectrodes delivered by a rotating mechanism;

[0091]FIG. 68 is a section view of the rotating mechanism for deployingelectrodes, taken generally along line 68-68 in FIG. 67 with theelectrodes withdrawn;

[0092]FIG. 69 is a view of the rotating mechanism shown in FIG. 68, witha vacuum applied to muscosal tissue and the electrodes extended;

[0093]FIG. 70 is a perspective view of a device for treating bodysphincters and adjoining tissue regions, which applies a vacuum tomucosal tissue to stabilize and present the tissue for the deployment ofstraight electrodes;

[0094]FIG. 71 is a side section view of the electrode deploymentmechanism of the device shown in FIG. 70;

[0095]FIGS. 72A and 72B are, respectively, left and right perspectiveviews of an integrated device for treating body sphincters and adjoiningtissue regions, and having graphical user interface;

[0096]FIG. 73 is a front view of the device shown in FIGS. 72A and 72Bshowing the components of the graphical user interface;

[0097]FIG. 74 is a view of the graphical user interface shown in FIG. 73showing the Standby screen before connection of a treatment device;

[0098]FIG. 75 is a view of the graphical user interface shown in FIG. 73showing the Standby screen after connection of a treatment device;

[0099]FIG. 76 is a view of the graphical user interface shown in FIG. 73showing the Standby screen after connection of a treatment device andafter an electrode channel has been disabled by selection;

[0100]FIG. 77 is a view of the graphical user interface shown in FIG. 73showing the Ready screen;

[0101]FIG. 78 is a view of the graphical user interface shown in FIG. 73showing the Ready screen while priming of cooling liquid takes place;

[0102]FIG. 79 is a view of the graphical user interface shown in FIG. 73showing the RF-On screen;

[0103]FIG. 80 is a view of the graphical user interface shown in FIG. 73showing the RF-On screen after an electrode channel has been disableddue to an undesired operating condition;

[0104]FIG. 81 is a view of the graphical user interface shown in FIG. 73showing the Pause screen;

[0105]FIG. 82 is a schematic view of the control architecture that theintegrated device and associated graphical user interface shown in FIGS.72A, 72B, and 73 incorporate; and

[0106]FIG. 83 is an anatomic view of the esophagus and stomach, withportions broken away and in section, showing the location of a compositelesion pattern effective in treating GERD.

[0107] The invention may be embodied in several forms without departingfrom its spirit or essential characteristics. The scope of the inventionis defined in the appended claims, rather than in the specificdescription preceding them. All embodiments that fall within the meaningand range of equivalency of the claims are therefore intended to beembraced by the claims.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0108] This Specification discloses various catheter-based systems andmethods for treating dysfunction of sphincters and adjoining tissueregions in the body. The systems and methods are particularly wellsuited for treating these dysfunctions in the upper gastrointestinaltract, e.g., in the lower esophageal sphincter and adjacent cardia ofthe stomach. For this reason, the systems and methods will be describedin this context.

[0109] Still, it should be appreciated that the disclosed systems andmethods are applicable for use in treating other dysfunctions elsewherein the body, which are not necessarily sphincter-related. For example,the various aspects of the invention have application in proceduresrequiring treatment of hemorrhoids, or incontinence, or restoringcompliance to or otherwise tightening interior tissue or muscle regions.The systems and methods that embody features of the invention are alsoadaptable for use with systems and surgical techniques that are notnecessarily catheter-based.

[0110] I. Anatomy of the Lower Esopageal Sphincter Region

[0111] As FIG. 1 shows, the esophagus 10 is a muscular tube that carriesfood from the mouth to the stomach 12. The muscles in the walls of theesophagus 10 contract in a wavelike manner, moving the food down to thestomach 12. The interior wall of the esophagus includes glands thatsecrete mucus, to aid in the movement of food by providing lubrication.The human esophagus is about twenty-five centimeters long.

[0112] The stomach 12, located in the upper left hand side of theabdomen, lays between the esophagus 10 and the small intestine 14. Inpeople and most animals, the stomach 12 is a simple baglike organ. Ahuman being's stomach is shaped much like a J.

[0113] The average adult stomach can hold a little over one quart (0.95liter). The stomach 12 serves as a storage place for food. Food in thestomach 12 is discharged slowly into the intestines 14. The stomach 12also helps digest food.

[0114] The upper end of the stomach connects with the esophagus 10 atthe cardiac notch 16, at the top of the J-shape. The muscular ringcalled the lower esophageal sphincter 18 surrounds the opening betweenthe esophagus 10 and the stomach 12. The funnel-shaped region of thestomach 12 immediately adjacent to the sphincter 18 is called the cardia20. The cardia 20 comprises smooth muscle. It is not a sphincter.

[0115] The lower esophageal sphincter 18 relaxes, or opens, to allowswallowed food to enter the stomach 12. The lower esophageal sphincter18, however, is normally closed, to keep the stomach 12 contents fromflowing back into the esophagus 10.

[0116] Another sphincter, called the pyloric sphincter 22, surrounds theduodenal opening of the stomach 12. The pyloric sphincter 22 keepsnon-liquid food material in the stomach 12 until it is processed into amore flowable, liquid form. The time that the stomach 12 retains foodvaries. Usually, the stomach 12 empties in three to five hours.

[0117] In a person suffering from GERD, the lower esophageal sphincter18 is subject to spontaneous relaxation. The sphincter 18 opensindependent of the normal swallowing function. Acidic stomach contentssurge upward into the esophagus 10, causing pain, discomfort, and damagethe mucosal wall of the esophagus 10.

[0118] The stomach 12 distends to accommodate various food volumes. Overtime, stomach distention can stretch the cardia 20 or otherwise causeloss of compliance in the cardia 20. Loss of compliance in the cardia 20can also pull the lower esophageal sphincter 18 open when the stomach 12is distended, even absent sphincter muscle relaxation. The sameundesired results occur: acidic stomach contents can surge upward intothe esophagus 10 with the attendant undesired consequences.

[0119] It should be noted that the views of the esophagus and stomachshown in FIG. 1 and elsewhere in the drawings are not intended to bestrictly accurate in an anatomic sense. The drawings show the esophagusand stomach in somewhat diagrammatic form to demonstrate the features ofthe invention.

[0120] II. Systems for Sphincters or Adjoining Tissue Regions

[0121] A. System Overview

[0122]FIG. 2 shows a system 24 for diagnosing and/or treatingdysfunction of the lower esophageal sphincter 18 and/or the adjoiningcardia 20 of the stomach 12.

[0123] The system 24 includes a treatment device 26. The device 26includes a handle 28 made, e.g., from molded plastic. The handle 28carries a flexible catheter tube 30. The catheter tube 30 can beconstructed, for example, using standard flexible, medical grade plasticmaterials, like vinyl, nylon, poly(ethylene), ionomer, poly(urethane),poly(amide), and poly(ethylene terephthalate). The handle 28 is sized tobe conveniently held by a physician, to introduce the catheter tube 30into the esophagus 10. The details of using the treatment device 28 willbe described later.

[0124] The handle 28 and the catheter tube 30 can form an integratedconstruction intended for a single use and subsequent disposal as aunit. Alternatively, the handle 28 can comprise a nondisposablecomponent intended for multiple uses. In this arrangement, the cathetertube 30, and components carried at the end of the catheter tube 30 (aswill be described), comprise a disposable assembly, which the physicianreleasably connects to the handle 28 at time of use and disconnects anddiscards after use. The catheter tube 30 can, for example, include amale plug connector that couples to a female plug receptacle on thehandle 28.

[0125] The system 24 may include an esophageal introducer 32. Theesophageal introducer 32 is made from a rigid, inert plastic material,e.g., poly(ethylene) or polyvinyl chloride. As will be described later,the introducer 32 aids in the deployment of the catheter tube 30 intothe esophagus 10 through the mouth and throat of a patient.

[0126] Alternatively, the catheter tube 30 may be deployed over a guidewire through the patient's mouth and pharynx, and into the esophagus 10,without use of an introducer 32, as will be described later. Stillalternatively, the catheter tube 30 may be passed through the patient'smouth and pharynx, and into the esophagus 10, without use of either aguide wire or introducer 32.

[0127] The catheter tube 30 has a distal end 34, which carries anoperative element 36. The operative element 36 can take different formsand can be used for either therapeutic purposes, or diagnostic purposes,or both.

[0128] The catheter tube 30 can carry a protection sheath 472 (see FIG.2) for the operative element 36. The sheath 472 slides along thecatheter tube 30 (as indicated by arrows 473 in FIG. 2) between aforward position enclosing the operative element 36 and a rearwardposition free of the operative element 36. When in the forward position,the sheath 472 prevents contact between tissue and the operative element36, thereby aiding in the deployment and removal of the operativeelement 36 through the patient's mouth and pharynx. When in the rearwardposition, the sheath 472 frees the operative element 36 for use.

[0129] As will be described in greater detail later, the operativeelement 36 can support, for example, a device for imaging body tissue,such as an endoscope, or an ultrasound transducer. The operative element36 can also support a device to deliver a drug or therapeutic materialto body tissue. The operative element 36 can also support a device forsensing a physiological characteristic in tissue, such as electricalactivity, or for transmitting energy to stimulate or form lesions intissue.

[0130] According to the invention, one function that the operativeelement 36 shown in the illustrated embodiment performs is to applyenergy in a selective fashion to a targeted sphincter or other bodyregion, which, for the purpose of illustration, are identified as thelower esophageal sphincter 18, or cardia 20, or both. The applied energycreates one or more lesions, or a prescribed pattern of lesions, belowthe mucosal surface of the esophagus 10 or cardia 20. The subsurfacelesions are formed in a manner that preserves and protects the mucosalsurface against thermal damage.

[0131] It has been discovered that natural healing of the subsurfacelesions leads to a physical tightening of the sphincter 18 and/oradjoining cardia 20. The subsurface lesions can also result in theinterruption of aberrant electrical pathways that may cause spontaneoussphincter relaxation. In any event, the treatment can restore normalclosure function to the sphincter 18.

[0132] In this arrangement, the system 24 includes a generator 38 tosupply the treatment energy. In the illustrated embodiment, thegenerator 38 supplies radio frequency energy, e.g., having a frequencyin the range of about 400 kHz to about 10 mHz. Of course, other forms ofenergy can be applied, e.g., coherent or incoherent light; heated orcooled fluid; resistive heating; microwave; ultrasound; a tissueablation fluid; or cryogenic fluid.

[0133] A cable 40 extending from the proximal end of the handle 28terminates with an electrical connector 42. The cable 40 is electricallycoupled to the operative element 36, e.g., by wires that extend throughthe interior of the handle 28 and catheter tube 30. The connector 42plugs into the generator 38, to convey the generated energy to theoperative element 36.

[0134] The system 24 also includes certain auxiliary processingequipment. In the illustrated embodiment, the processing equipmentcomprises an external fluid delivery apparatus 44 and an externalaspirating apparatus 46.

[0135] The catheter tube 30 includes one or more interior lumens (notshown) that terminate in fittings 48 and 50, located on the handle 28.One fitting 40 connects to the fluid delivery apparatus 44, to conveyprocessing fluid for discharge by or near the operative element 36. Theother fitting 50 connects to the aspirating apparatus 46, to conveyaspirated material from or near from the operative element 36 fordischarge.

[0136] The system 24 also includes a controller 52. The controller 52,which preferably includes a central processing unit (CPU), is linked tothe generator 38, the fluid delivery apparatus 44, and the aspiratingapparatus 46. Alternatively, the aspirating apparatus 46 can comprise aconventional vacuum source typically present in a physician's suite,which operates continuously, independent of the controller 52.

[0137] The controller 52 governs the power levels, cycles, and durationthat the radio frequency energy is distributed to the operative element36, to achieve and maintain power levels appropriate to achieve thedesired treatment objectives. In tandem, the controller 52 also governsthe delivery of processing fluid and, if desired, the removal ofaspirated material.

[0138] The controller 52 includes an input/output (I/O) device 54. TheI/O device 54 allows the physician to input control and processingvariables, to enable the controller to generate appropriate commandsignals. The I/O device 54 also receives real time processing feedbackinformation from one or more sensors associated with the operativeelement (as will be described later), for processing by the controller52, e.g., to govern the application of energy and the delivery ofprocessing fluid. The I/O device 54 also includes a graphical userinterface (GUI), to graphically present processing information to thephysician for viewing or analysis. Further details regarding the GUIwill be provided later.

[0139] B. Operative Elements

[0140] The structure of the operative element 36 can vary. Variousrepresentative embodiments will be described.

[0141] (i) Bipolar Devices

[0142] In the embodiment shown in FIGS. 3 to 7, the operative element 36comprises a three-dimensional basket 56. The basket 56 includes one ormore spines 58, and typically includes from four to eight spines 58,which are assembled together by a distal hub 60 and a proximal base 62.In FIG. 3, the spines 58 are equally circumferentially spaced apart inside-by-side pairs.

[0143] Each spine 58 preferably comprises a flexible tubular body made,e.g. from molded plastic, stainless steel, or nickel titanium alloy. Thecross sectional shape of the spines 58 can vary, possessing, e.g., acircular, elliptical, square, or rectilinear shape. In the illustratedembodiment, the spines 58 possess a rectilinear shape to resisttwisting. Further examples of specific configurations for the spines 58will be provided later.

[0144] Each spine 58 can be surrounded by a sleeve 64 (see FIG. 7) thatis preferably textured to impart friction. Candidate materials for thesleeve 64 include knitted Dacron® material and Dacron® velour.

[0145] Each spine 58 carries an electrode 66 (see FIGS. 5 and 7). In theillustrated embodiment, each electrode 66 is carried within the tubularspine 58 for sliding movement. Each electrode 66 slides from a retractedposition, withdrawn in the spine 58 (shown in FIGS. 3, 4, and 6), and anextended position, extending outward from the spine 58 (see FIGS. 5 and7) through a hole in the spine 58 and sleeve 64.

[0146] A push-pull lever 68 on the handle 28 is coupled by one or moreinterior wires to the sliding electrodes 66. The lever 68 controlsmovement electrodes between the retracted position (by pulling rearwardon the lever 68) and the extended position (by pushing forward on thelever 68).

[0147] The electrodes 66 can be formed from various energy transmittingmaterials. In the illustrated embodiment, for deployment in theesophagus 10 or cardia 20, the electrodes 66 are formed from nickeltitanium. The electrodes 66 can also be formed from stainless steel,e.g., 304 stainless steel, or, as will be described later, a combinationof nickel titanium and stainless steel. The electrodes 66 havesufficient distal sharpness and strength to penetrate a desired depthinto the smooth muscle of the esophageal or cardia 20 wall. The desireddepth can range from about 4 mm to about 5 mm.

[0148] To further facilitate penetration and anchoring in the esophagus10 or cardia 20, each electrode 66 is preferably biased with a bend.Movement of the electrode 66 into the spine 58 overcomes the bias andstraightens the electrode 66.

[0149] In the illustrated embodiment (see FIG. 5), each electrode 66 isnormally biased with an antegrade bend (i.e., bending toward theproximal base 62 of the basket 56). Alternatively, each electrode 66 canbe normally biased toward an opposite retrograde bend (i.e., bendingtoward the distal hub 60 of the basket 58).

[0150] As FIG. 7 shows, an electrical insulating material 70 is coatedabout the proximal end of each electrode 66. For deployment in theesophagus 10 or cardia 20, the length of the material 70 ranges fromabout 80 to about 120 mm. The insulating material 70 can comprise, e.g.,a Polyethylene Terephthalate (PET) material, or a polyimide or polyamidematerial. For deployment in the esophagus 10 or cardia 20, eachelectrode 66 preferably presents an exposed, non-insulated conductivelength of about 8 mm, providing an exposed surface area at the distalend of each electrode 66 of preferably about 0.1 mm² to 100 cm².

[0151] When the distal end of the electrode 66 penetrating the smoothmuscle of the esophageal sphincter 18 or cardia 20 transmits radiofrequency energy, the material 70 insulates the mucosal surface of theesophagus 10 or cardia 20 from direct exposure to the radio frequencyenergy. Thermal damage to the mucosal surface is thereby avoided. Aswill be described later, the mucosal surface can also be actively cooledduring application of radio frequency energy, to further protect themucosal surface from thermal damage.

[0152] The ratio between exposed and insulated regions on the electrodes66 affects the impedance of the electrodes 66 during use. Generallyspeaking, the larger the exposed region is compared to the insulatedregion, a lower impedance value can be expected, leading to a fewerincidences of power shut-offs due to high impedance.

[0153] Of course, a greater or lesser number of spines 58 and/orelectrodes 66 can be present, and the geometric array of the spines 58and electrodes 66 can vary.

[0154] In the embodiment shown in FIG. 3, an expandable structure 72comprising a balloon is located within the basket 56. The balloonstructure 72 can be made, e.g., from a Polyethylene Terephthalate (PET)material, or a polyamide (non-compliant) material, or a radiationcrosslinked polyethylene (semi-compliant) material, or a latex material,or a silicone material, or a C-Flex (highly compliant) material.Non-compliant materials offer the advantages of a predictable size andpressure feedback when inflated in contact with tissue. Compliantmaterials offer the advantages of variable sizes and shape conformanceto adjacent tissue geometries.

[0155] The balloon structure 72 presents a normally, generally collapsedcondition, as FIGS. 3 and 6 show). In this condition, the basket 56 isalso normally collapsed about the balloon structure 72, presenting a lowprofile for deployment into the esophagus 10.

[0156] To aid in the collapse of the basket 56 (see FIG. 8), one end(hub 60 or base 62) of the basket 56 can be arranged to slidelongitudinally relative to the other end of the basket 56, which isaccordingly kept stationary. A stylet 74 attached to the slidable end ofthe basket 56 (which, in FIG. 8, is the base 62) is controlled, e.g., bya push-pull mechanism on the handle 28. The stylet 74, when pulled,serves to move the ends 58 and 60 of the basket 56 apart when theballoon structure 72 is collapsed. A full collapse of the basket 56 isthereby possible (as FIG. 8 shows) to minimize the overall profile ofthe basket 56 for passage through the esophagus 10. The push-pullmechanism can include a lock to hold the stylet 74 stationary, tomaintain the basket 56 in the fully collapsed condition duringdeployment.

[0157] The catheter tube 30 includes an interior lumen, whichcommunicates with the interior of the balloon structure 72. A fitting 76(e.g., a syringe-activated check valve) is carried by the handle 28. Thefitting 76 communicates with the lumen. The fitting 76 couples the lumento a syringe 78 (see FIGS. 4 and 5). The syringe 78 injects fluid underpressure through the lumen into the balloon structure 72, causing itsexpansion.

[0158] Expansion of the balloon structure 72 urges the basket 56 to openand expand (as FIGS. 4, 5, and 7 show). The force exerted by the balloonstructure 72, when expanded, is sufficient to exert an opening forceupon the tissue surrounding the basket 56. Preferably, for deployment inthe esophagus 10 or cardia 20, the magnitude of the force exerted by theballoon structure 72 is between about 0.01 to 0.5 lbs.

[0159] For deployment in the lower esophageal sphincter 18, the diameterof the balloon structure 72, when expanded, can be optimized at about 2cm to 3 cm. For deployment in the cardia 20, the diameter of the balloonstructure 72, when expanded, can be optimized at about 4 cm to about 6cm.

[0160] In the illustrated embodiment, the controller 52 conditionsselected pairs of electrodes 66 to operate in a bipolar mode. In thismode, one of the electrodes comprises the transmitter and the otherelectrode comprises the return for the transmitted energy. The bipolarelectrode pairs can comprise adjacent side-by-side electrodes 66 on agiven spine, or electrodes 66 spaced more widely apart on differentspines.

[0161] In the illustrated embodiment (see FIG. 7), each electrode 66carries at least one temperature sensor 80. Each electrode can carry twotemperature sensors 80, one to sense temperature conditions near theexposed distal end of the electrode 66, and the other to sensetemperature conditions in the insulated material 70. Preferably, thesecond temperature sensor 80 is located on the corresponding spine 58,which rests against the muscosal surface when the balloon structure 72is inflated.

[0162] In use (see FIGS. 9 to 19), the patient lies awake in a reclinedor semi-reclined position. If used, the physician inserts the esophagealintroducer 32 through the throat and partially into the esophagus 10.The introducer 32 is pre-curved to follow the path from the mouth,through the pharynx, and into the esophagus 10. The introducer 32 alsoincludes a mouth piece 82, on which the patient bites to hold theintroducer 32 in position. The introducer 32 provides an open,unobstructed path into the esophagus 10 and prevents spontaneous gagreflexes during the procedure.

[0163] As before explained, the physician need not use the introducer32. In this instance, a simple mouth piece 82, upon which the patientbites, is used.

[0164] The physician preferably first conducts a diagnostic phase of theprocedure, to localize the site to be treated. As FIGS. 9 and 10 show, avisualization device can be used for this purpose. The visualizationdevice can comprise an endoscope 84, or other suitable visualizingmechanism, carried at the end of a flexible catheter tube 86. Thecatheter tube 86 for the endoscope 84 includes measured markings 88along its length. The markings 88 indicate the distance between a givenlocation along the catheter tube 86 and the endoscope 84.

[0165] As FIGS. 9 and 10 show, the physician passes the catheter tube 86through the patient's mouth and pharynx, and into the esophagus 10,while visualizing through the endoscope 84. Relating the alignment ofthe markings 88 to the mouth piece 82, the physician can gauge, ineither relative or absolute terms, the distance between the patient'smouth and the endoscope 84 in the esophagus 10. When the physicianvisualizes the desired treatment site (lower esophageal sphincter 18 orcardia 20) with the endoscope 84, the physician records the markings 88that align with the mouth piece 82.

[0166] The physician next begins the treatment phase of the procedure.As FIGS. 11 and 12 show, the physician passes the catheter tube 30carrying the operative element 36 through the introducer 32. For thepassage, the expandable balloon structure 72 is in its collapsedcondition, and the electrodes 66 are in their retracted position. Thephysician can keep the endoscope 84 deployed for viewing the deploymentof the operative element 36, either separately deployed in aside-by-side relationship with the catheter tube 30, or (as will bedescribed later) by deployment through a lumen in the catheter tube 30or deployment of the structure 72 through a lumen in the endoscope 84itself. If there is not enough space for side-by-side deployment of theendoscope 84, the physician deploys the endoscope 84 before and afterdeployment of the structure 72.

[0167] In the illustrated embodiment, the catheter tube 30 includesmeasured markings 90 along its length. The measured markings 90 indicatethe distance between a given location along the catheter tube 30 and theoperative element 36. The markings 90 on the catheter tube 30 correspondin spacing and scale with the measured markings along the endoscopecatheter tube 86. The physician can thereby relate the markings 90 onthe catheter tube 30 to gauge, in either relative or absolute terms, thelocation of the operative element 36 inside the esophagus 10. When themarkings 90 indicate that the operative element 36 is at the desiredlocation (earlier visualized by the endoscope 84), the physician stopspassage of the operative element 36. The operative element 36 is nowlocated at the site targeted for treatment.

[0168] In FIG. 12, the targeted site is shown to be the lower esophagealsphincter 18. In FIG. 15, the targeted site is shown to be the cardia 20of the stomach 12.

[0169] Once located at the targeted site, the physician operates thesyringe 78 to convey fluid or air into the expandable balloon structure72. The structure 72, and with it, the basket 56, expand, to makeintimate contact with the mucosal surface, either with the sphincter(see FIG. 13) or the cardia 20 (FIG. 16). The expanded balloon structure72 serves to temporarily dilate the lower esophageal sphincter 18 orcardia 20, to remove some or all the folds normally present in themucosal surface. The expanded balloon structure 72 also places thespines 58 in intimate contact with the mucosal surface.

[0170] The physician pushes forward on the lever 68 to move theelectrodes 66 into their extended position. The electrodes 66 pierce andpass through the mucosal tissue into the smooth muscle tissue of thelower esophageal sphincter 18 (FIG. 14) or cardia 20 (FIGS. 17 and 18).

[0171] The physician commands the controller 52 to apply radio frequencyenergy between the transmitting and receiving electrodes 66 in eachpair. The energy can be applied simultaneously by all pairs ofelectrodes 66, or in any desired sequence.

[0172] The energy ohmically heats the smooth muscle tissue between thetransmitting and return electrodes 66. The controller 52 samplestemperatures sensed by the sensors 80 to control the application ofenergy. When each electrode 66 in a given pair carries at least onetemperature sensor 80, the controller 52 can average the sensedtemperature conditions or select the maximum temperature conditionsensed for control purposes.

[0173] The controller 52 processes the sensed temperatures in a feedbackloop to control the application of energy. The GUI can also display thesensed temperatures and the applied energy levels. Alternatively, thephysician can manually control the energy levels based upon thetemperature conditions displayed on the GUI.

[0174] Preferably, for a region of the lower esophageal sphincter 18 orcardia 20, energy is applied to achieve tissue temperatures in thesmooth muscle tissue in the range of 55° C. to 95° C. In this way,lesions can typically be created at depths ranging from one to fourmillimeters below the muscosal surface. Typical energies range, e.g.,between 100 and 1000 joules per electrode pair.

[0175] It is desirable that the lesions possess sufficient volume toevoke tissue healing processes accompanied by intervention offibroblasts, myofibroblasts, macrophages, and other cells. The healingprocesses results in a contraction of tissue about the lesion, todecrease its volume or otherwise alter its biomechanical properties. Thehealing processes naturally tighten the smooth muscle tissue in thesphincter 18 or cardia 20. The bipolar nature of the energy path betweenthe electrodes 66 creates, for a given amount of energy, lesions ofgreater volume than is typically created in a monopolar fashion.

[0176] To create greater lesion density in a given targeted tissue area,it is also desirable to create a pattern of multiple lesions, e.g., inrings along the targeted treatment site in the lower esophagealsphincter 18 or cardia 20.

[0177] Various lesion patterns 92 can be achieved. A preferred pattern(shown in FIG. 20 for the cardia 20) comprises several rings 94 oflesions 96 about one centimeter apart, each ring 94 comprising at leasteight lesions 96. For example, a preferred pattern 92 comprise six rings94, each with eight lesions 96. In the cardia 20, as FIG. 20 shows, therings 94 are concentrically spaced about the opening funnel of thecardia 20. In the lower esophageal sphincter 18, the rings 94 areaxially spaced along the esophagus 10.

[0178] The physician can create a given ring pattern 92 by expanding theballoon structure 72 and extending the electrodes 66 at the targetedtreatment site, to form a first set of four lesions. The physician thenwithdraws the electrodes 66, collapses the balloon structure 72, androtates the catheter tube 30 by a desired amount. The physician thenagain expands the structure 72 and again extends the electrodes 66, toachieve a second set of four lesions. The physician repeats thissequence until a desired ring 94 of lesions 96 is formed. Additionalrings 94 of lesions 96 can be created by advancing the operative elementaxially, gauging the ring separation by the markings 90 on the cathetertube 30.

[0179] Other, more random or eccentric patterns of lesions can be formedto achieve the desired density of lesions within a given targeted site.

[0180] The bipolar operative element 36 can be used in the mannerdescribed to treat both the cardia 20 and the lower esophageal sphincter18 in a single procedure. Alternatively, the operative element 36 can beused in the manner described to treat either the cardia 20 or the loweresophageal sphincter 18 individually.

[0181] In one embodiment, at least one spine 58 (and preferably allspines) includes an interior lumen 98 (see FIG. 7). The fluid deliveryapparatus 44 conveys processing fluid F through the lumen 98 fordischarge at the treatment site. The processing fluid F can comprise,e.g., saline or sterile water, to cool the mucosal surface while energyis being applied by the electrode 66 to ohmically heat muscle beneaththe surface.

[0182] In this arrangement (see FIG. 5), the catheter tube 30 includes adistal tail 100, which extends beyond the hub 60 of the basket 56. Aninterior lumen 102 extends through the tail 100 and the interior of theballoon structure 72 to connect to the fitting 48. The aspiratingapparatus 46 draws aspirated material and the processing fluid throughthis lumen 102 for discharge. This arrangement provides self-containedaspiration for the operative element 36.

[0183] In an alternative embodiment suited for treatment of the loweresophageal sphincter 18 outside the stomach 12 (see FIG. 11), the mouthpiece 82 of the esophageal introducer 32, if used, includes anaspiration port 104. The aspiration apparatus 46 is coupled to this port104. In this arrangement, processing fluid introduced at the treatmentsite is drawn through the introducer 32 surrounding the catheter tube 30and into the aspiration apparatus 46 for discharge. In this embodiment,the operative element 36 need not include the self contained, interioraspiration lumen 102.

[0184] (ii) Structures Shaped for the Cardia

[0185] As FIG. 1 shows, the cardia 20 presents a significantly differenttopology than the lower esophageal sphincter 18. First, the surface areaof the cardia 20 is larger than the lower esophageal sphincter 18.Second, the surface area of the cardia 20 expands with distance from thelower esophageal sphincter 18. The cardia 20 is therefore “funnel”shaped, compared to the more tubular shape of the lower esophagealsphincter 18.

[0186] The different topologies can be accommodated by using a family ofoperative elements having different shapes. One such operative elementhas a size and geometry better suited for deployment in the loweresophageal sphincter 18 than the cardia 20, if desired). Another suchoperative element has a larger size and different geometry better suitedfor deployment in the cardia 20 than the lower esophageal sphincter.However, it is preferred to provide a single operative element that canbe effectively deployed in both regions.

[0187] The location and the orientation of optimal, intimate contactbetween an operative element and the targeted tissue also differ in thecardia 20, compared to the lower esophageal sphincter 18. In the loweresophageal sphincter 18, optimal, intimate contact occurs generallyabout the mid-region of the operative element, to thereby conform to thegenerally tubular shape of the sphincter 18. In the cardia 20, optimal,intimate contact occurs generally more about the proximal end ofoperative device, to thereby conform to the funnel shape of the cardia20.

[0188] (a) Proximally Enlarged, Shaped Structures

[0189] FIGS. 21 to 23 show an operative element 106 having a shapedgeometry and electrode configuration well suited for use in the cardia20. The operative element 106 shares many features of the operativeelement 36 shown in FIG. 5, and common reference numbers are thusassigned.

[0190] Like the previously described element 36, the operative element106 comprises an array of spines 58 forming a basket 56, which iscarried at the distal end of a catheter tube 30. Like the previouslydescribed element 36, the operative element 106 includes electrodes 66on the spines 58 that can be retracted (FIG. 21) or extended (FIG. 22).As illustrated, the electrodes 66 are likewise bent in an antegradedirection.

[0191] Like the previously described element 36, the operative element106 includes an inner balloon structure 72 that expands to open thebasket 56 and place it in intimate contact with the cardia 20 forextension of the electrodes 66.

[0192] The balloon structure 72, when expanded, as shown in FIG. 22,possesses a preformed shape achieved e.g., through the use ofconventional thermoforming or blow molding techniques. The structure 72possesses a “pear” shape, being more enlarged at its proximal end thanat its distal end. This preformed pear shape presents an enlargedproximal surface for contacting the cardia 20 (see FIG. 23). Thepreformed pear shape better conforms to the funnel shaped topography ofthe cardia 20 than a circular shape. The pear shape, when in intimatecontact with the cardia 20, establishes a secure anchor point for thedeployment of the electrodes 66.

[0193] As also shown in FIGS. 22 and 23, the electrodes 66 themselvesare repositioned to take advantage of the pear shape of the underlyingballoon structure 72. The electrodes 66 are positioned proximally closerto the enlarged proximal base of the structure 72 than to its distalend. As FIGS. 24 and 25 show, the proximally located electrodes 66 canalso be bent in a retrograde bent direction on the pear-shaped element106.

[0194] In use (as FIGS. 23 and 25 show), the physician deploys theoperative element 106 into the stomach 12. The physician expands theelement 106 and then pulls rearward on the catheter tube 30. This placesthe enlarged proximal base of the structure 106 in contact with thecardia 20. The physician next extends the electrodes 66 into the cardia20 and proceeds with the ablation process. Multiple lesion patterns canbe created by successive extension and retraction of the electrodes,accompanied by rotation and axial movement of the catheter tube 30 toreposition the structure 106.

[0195] If enough space is present, the physician can retroflex anendoscope, also deployed in the stomach 12, to image the cardia 20 asdeployment of the electrodes 66 and lesion formation occur. Typically,however, there is not enough space for side-by-side deployment of theendoscope, and the physician views the cardia 20 before and after thelesion groups are formed.

[0196] As FIGS. 23 and 25 show, the purposeful proximal shaping of theoperative element 106 and the proximal location of the antegrade orretrograde electrodes 66 make the operative element 106 well suited foruse in the cardia 20.

[0197] In FIGS. 22 and 24, the electrodes 66 are not arranged in bipolarpairs. Instead, for purposes of illustration, the electrodes 66 areshown arranged in singular, spaced apart relation. In this arrangement,the electrodes 66 are intended for monopolar operation. Each electrode66 serves as a transmitter of energy, and an indifferent patch electrode(not shown) serves as a common return for all electrodes 66. It shouldbe appreciated, however, the operative element 106 could include bipolarpairs of electrodes 66 as shown in FIG. 5, if desired.

[0198] (b) Disk Shaped Expandable Structures

[0199]FIG. 26 shows another operative element 108 shaped for deploymentin the cardia 20. This element 108 shares many features with the element36 shown in FIG. 5, and common reference numbers have also beenassigned.

[0200] In FIG. 26, the expandable balloon structure 72 within theelement 108 has been preformed, e.g., through the use of conventionalthermoforming or blow molding techniques, to present a disk or donutshape. The disk shape also provides an enlarged proximal surface forcontacting the cardia 20, to create a secure anchor for the deploymentof the electrodes 66.

[0201] The physician deploys the operative element 108 into the stomach12, preferably imaging the cardia 20 as deployment occurs. The physicianexpands the disk-shaped element 108 and pulls rearward on the cathetertube 30, to place the element 108 in contact with the cardia 20. Thephysician extends the electrodes into the cardia 20 and proceeds withthe ablation process. Lesion patterns are formed by successive extensionand retraction of the electrodes 66, accompanied by rotation and axialmovement of the catheter tube 30.

[0202] As FIG. 26 shows, antegrade bent electrodes 66 are proximallymounted about the disk-shaped expandable element 108. Retrograde bentelectrodes could also be deployed.

[0203] (c) Complex Shaped Structures Providing Multiple Anchor Points

[0204]FIGS. 27 and 28 show another operative element 110 having ageometry well suited for deployment in the cardia 20. The balloonstructure 72 within the element 110 is preformed, e.g., through the useof conventional thermoforming or blow molding techniques, to possesses acomplex peanut shape. The complex shape provides multiple surfacecontact regions, both inside and outside the cardia 20, to anchor theelement 110 for deployment of the electrodes 66.

[0205] In FIG. 27, a reduced diameter portion 112 of the expandedstructure 72 contacts the lower esophageal sphincter region. A largerdiameter main portion 114 of the expanded structure 72 rests in intimatecontact against the cardia 20 of the stomach 12.

[0206] In an alternative peanut shaped configuration (see FIG. 28), thestructure 72 includes a first reduced diameter portion 116 to contactthe esophagus 10 above the lower esophageal sphincter 18. The structure72 includes a second reduced portion 118 to contact the lower esophagealsphincter 18 region of the esophagus 10. The structure includes a third,larger diameter main portion 120 to rest in intimate contact against thecardia 20 of the stomach 12.

[0207] The peanut shaped configurations shown in FIGS. 27 and 28 providemultiple points of support for operative element 110 both inside andoutside the stomach 12, to thereby stabilize the electrodes.

[0208] In FIGS. 27 and 28, antegrade bent electrodes 66 are showndeployed in the cardia 20. Retrograde bent electrodes could also bedeployed.

[0209] C. The Electrodes

[0210] (i) Electrode Shapes

[0211] Regardless of the shape of the operative element and its regionof deployment in the body, the electrodes 66 can be formed in varioussizes and shapes. As FIG. 30 shows, the electrodes 66 can possess acircular cross sectional shape. However, the electrodes 66 preferablypossess a cross section that provides increased resistance to twistingor bending as the electrodes penetrate tissue. For example, theelectrodes 66 can possess a rectangular cross section, as FIG. 32 shows.Alternatively, the electrodes 66 can possess an elliptical crosssection, as FIG. 31 shows. Other cross sections, e.g., conical orpyramidal, can also be used to resist twisting.

[0212] The surface of the electrode 66 can, e.g., be smooth, ortextured, or concave, or convex. The preceding description describeselectrodes 66 bent in either an antegrade or retrograde direction overan arc of ninety degrees or less. The bend provides a secure anchoragein tissue. Retraction of the electrodes 66 into the spines 58 overcomesthe bias and straightens the electrode 66 when not in use.

[0213] In FIG. 29, the electrode 66 is biased toward a “pigtail” bend,which spans an arc of greater than ninety degrees. The increased arc ofthe bend enhances the tissue-gripping force, thereby providing a moresecure anchorage in tissue. As before, retraction of the electrodes 66into the spines 58 overcomes the bias and straightens the electrode 66when not in use.

[0214] A given electrode 66 can comprise a hybrid of materials, e.g.,stainless steel for the proximal portion and nickel titanium alloy forthe distal portion. The nickel titanium alloy performs best in a curvedregion of the electrode 66, due to its super-elastic properties. The useof stainless steel in the proximal portion can reduce cost, byminimizing the amount of nickel titanium alloy required.

[0215] The different materials may be joined, e.g., by crimping,swaging, soldering, welding, or adhesive bonding, which provideelectrical continuity between or among the various materials.

[0216] One or both of the materials may be flattened to an oval geometryand keyed together to prevent mutual twisting. In a preferredembodiment, the proximal portion comprises an oval stainless steel tube,into which a distal curved region having a round cross section and madeof nickel titanium is slipped and keyed to prevent mutual twisting.

[0217] (ii) Electrode Penetration Depth

[0218] The depth of electrode penetration can also be controlled, toprevent puncture through the targeted tissue region.

[0219] In one embodiment, the push-pull lever 68 on the handle 28, whichcontrols movement electrodes 66, can include a rachet 118 or detentmechanism (see FIG. 3) that provides a tactile indication of electrodeadvancement. For each click of the rachet mechamism 118 as the lever 68is moved forward or rearward, the physician knows that the electrodeshave traveled a set distance, e.g., 1 mm.

[0220] Alternatively, or in combination, the electrode 66 can carry alimit collar 121 (see FIG. 33). The limit collar 121 contacts surfacetissue when a set maximum desired depth of electrode penetration hasbeen reached. The contact between the collar 121 and surface tissueresists further advancement of the electrode 66. The physician sensesthe contact between the collar 121 and surface tissue by the increasedresistance to movement of the lever 68. The physician thereby knows thatthe maximum desired depth of tissue penetration has been reached and toextend the electrodes 66 no further.

[0221] An electrical measurement can also be made to determinepenetration of an electrode 66 in tissue. For example, by applyingelectrical energy at a frequency (e.g., 5 kHz) less than that appliedfor lesion formation, impedance of a given electrode 66 can be assessed.The magnitude of the impedance varies with the existence of tissuepenetration and the depth of tissue penetration. A high impedance valueindicates the lack of tissue penetration. The impedance value is loweredto the extent the electrode penetrates the tissue.

[0222] (iii) Movement of Electrodes

[0223] As before described, it is desirable to be able to create apattern of multiple lesions to create greater lesion density. Theprevious discussions in this regard were directed to achieving thesepatterns by successive extension and retraction of the electrodes 66,accompanied by rotation and axial movement of the catheter tube 30.

[0224] An alternative embodiment is shown in FIG. 34, which achievescreation of lesion patterns movement without axial and, if desired,rotational movement of the catheter tube 30. In this embodiment, thebasket 56 has an array of spines 58, as generally shown, e.g., in FIG.22 or 24. As FIG. 34 shows, each spine 58 in the alternative embodimentincludes an inner carrier 122 mounted for axial sliding movement withina concentric outer sleeve 124. In this arrangement, a push-pull stylet126 controlled by another lever on the handle (not shown) axially movesthe carrier 122 within the outer sleeve 124 (as shown by arrows 125 inFIG. 34).

[0225] A tissue penetrating electrode 66 of the type already describedis supported by the carrier 122. The electrode 66 can be moved by theoperator (using the handle-mounted lever 68, as shown in FIG. 5) from aretracted position within the carrier 122 and an extended position,projecting from a guide hole 128 in the carrier 122 (which FIG. 34shows). When in the extended position, the electrode 66 also projectsthrough a window 130 in the outer sleeve 124 for tissue penetration. Thewindow 130 has a greater axial length than the guide hole 128. Theextended electrode 66 can thereby be moved by moving the carrier 122 (asshown by arrows 127 in FIG. 34) and thereby positioned in a range ofpositions within the window 130.

[0226] For example, in use, the physician moves the carrier 122 so thatthe guide hole 128 is aligned with the leading edge of the window 130.The push-pull stylet 126 can be controlled, e.g., with a detentmechanism that stops forward advancement or otherwise gives a tactileindication when this alignment occurs. External markings on the handlecan also visually provide this information. The physician moves theelectrodes 66 into their respective extended position, to penetratetissue. After energy sufficient to form a first ring pattern of lesionsis applied, the physician withdraws the electrodes 66 into the carriers122.

[0227] The physician now moves the electrodes 66 axially rearward,without moving the catheter tube 30, by pulling the push-pull stylet 126rearward. If desired, the physician can rotate the catheter tube 30 toachieve a different circumferential alignment of electrodes 66. Thedetent mechanism or the like can click or provide another tactileindication that the guide hole 128 in each spine is aligned with a midportion of the respective window 130. Markings on the handle can alsoprovide a visual indication of this alignment. The physician extends theelectrodes 66 through the window 130. This time, the electrode 66penetrate tissue in a position axially spaced from the first ring ofpenetration. Energy is applied sufficient to form a second ring patternof lesions, which likewise are axially spaced from the first ring. Thephysician withdraws the electrodes 66 into the carriers.

[0228] The physician can now move the carriers 122 to move the guideholes 128 to a third position at the trailing edge of each window 130,still without axially moving the catheter tube 30. The catheter tube 30can be rotated, if desired, to achieve a different circumferentialorientation. The physician repeats the above-described electrodedeployment steps to form a third ring pattern of lesions. The physicianwithdraws the electrodes 66 into the carriers 122 and withdraws thebasket 56, completing the procedure.

[0229] As FIG. 35 shows, each carrier 122 can hold more than oneelectrode 66. In this arrangement, the electrodes 66 on each carrier 122are extendable and retractable through axially spaced-apart guide holes128 in the carrier 122. In this arrangement, the outer sleeve 124includes multiple windows 130 registering with the electrode guide holes128. In this arrangement, the physician is able to simultaneously createmultiple ring patterns. Further, the physician can axially shift theelectrodes 66 and create additional ring patterns by shifting thecarrier 122, and without axial movement of the catheter tube 30.

[0230] In the foregoing descriptions, each spine 58 comprises astationary part of the basket 56. As FIGS. 36 and 37 show, an array ofmovable spines 132, not joined to a common distal hub, can be deployedalong the expandable balloon structure 72. In FIGS. 36 and 37, theexpandable structure 72 is shown to have a disk-shaped geometry and isdeployed in the cardia 20 of the stomach 12. Two movable spines 132 areshown for the purpose of illustration, but it should be appreciated thatfewer or greater number of movable spines 132 could be deployed.

[0231] In this embodiment, the proximal ends of the spines 132 arecoupled, e.g., to a push-pull stylet on the handle (not shown). Undercontrol of the physician, the spines 132 are advanced to a desiredposition along the structure 72 in the tissue contact region, as shownby arrows 133 in FIGS. 36 and 37. Each movable spine 132 can carry asingle electrode 66 (as FIG. 37 shows) or multiple electrodes 66 (asshown in FIG. 36). Regardless, each electrode 66 can be extended andretracted relative to the movable spine 132.

[0232] In use, the physician positions the movable spines 132 anddeploys the electrode 66 or electrodes to create a first lesion patternin the contact region. By retracting the electrode 66 or electrodes, thephysician can relocate the movable spines 132 to one or more otherpositions (with or without rotating the catheter tube 30). By deployingthe electrode 66 or electrodes in the different positions by moving thespines 132, the physician can form complex lesion patterns in the tissuecontact region without axial movement of the catheter tube 30.

[0233] In yet another alternative embodiment (see FIG. 38), an operativeelement 134 can comprise a catheter tube 30 that carries at its distalend a single mono-polar electrode 66 (or a bipolar pair of electrodes),absent an associated expandable structure. The distal end of thecatheter tube 30 includes a conventional catheter steering mechanism 135to move the electrode 66 (or electrodes) into penetrating contact with adesired tissue region, as arrows 137 in FIG. 38 show). The electrode 66can carry a limit collar 121 (as also shown in FIG. 33) to resistadvancement of the electrode 66 beyond a desired penetration depth.Using the operative element 134 shown in FIG. 38, the physician forms adesired pattern of lesions by making a succession of individualmono-polar or bipolar lesions.

[0234] (iv) Drug Delivery Through Electrodes

[0235] A given electrode 66 deployed by an operative device in asphincter or other body region can also be used to deliver drugsindependent of or as an adjunct to lesion formation. In thisarrangement, the electrode 66 includes an interior lumen 136 (as FIG. 35demonstrates for the purpose of illustration).

[0236] As before explained, a submucosal lesion can be formed byinjecting an ablation chemical through the lumen 136, instead of or incombination with the application of ablation energy by the electrode.

[0237] Any electrode 66 possessing the lumen 136 can also be used todeliver drugs to the targeted tissue site. For example, tissue growthfactors, fibrosis inducers, fibroblast growth factors, or sclerosantscan be injected through the electrode lumen 136, either without or as anadjunct to the application of energy to ablate the tissue. Tissuebulking of a sphincter region can also be achieved by the injection ofcollagen, dermis, cadaver allograft material, or PTFE pellets throughthe electrode lumen 136. If desired, radio frequency energy can beapplied to the injected bulking material to change its physicalcharacteristics, e.g., to expand or harden the bulking material, toachieve a desired effect.

[0238] As another example, the failure of a ring of muscle, e.g., theanal sphincter or the lower esophageal sphincter 18, called achalasia,can also be treated using an electrode 66 having an interior lumen 136,carried by an operative device previously described. In thisarrangement, the electrode 66 is deployed and extended into thedysfunctional sphincter muscle. A selected exotoxin, e.g., serotype A ofthe Botulinum toxin, can be injected through the electrode lumen 136 toproduce a flaccid paralysis of the dysfunctional sphincter muscle.

[0239] For the treatment of achalasia of a given sphincter, theelectrode 66 carried by an operative device can also be conditioned toapply stimulant energy to nerve tissue coupled to the dysfunctionalmuscle. The stimulant energy provides an observable positive result(e.g., a relaxation of the sphincter) when targeted nerve tissue is inthe tissue region occupied by the electrode 66. the observable positiveresult indicates that position of the electrode 66 should be maintainedwhile applying ablation energy to the nerve tissue. Application of thenerve ablation energy can permanently eliminate the function of atargeted nerve branch, to thereby inactivate a selected sphinctermuscle. Further details of the application of ablation energy to nervetissue can be found in co-pending application entitled “Systems AndMethods For Ablating Discrete Motor Nerve Regions.”

[0240] (v) Surface Electrodes

[0241] As earlier mentioned, one of the complications of GERD is thereplacement of normal esophageal epithelium with abnormal (Barrett's)epithelium. FIGS. 39 and 40 show an operative element 138 for thetreatment of this condition.

[0242] The operative element 138 includes an expandable balloonstructure 140 carried at the distal end of a catheter tube 30. FIG. 39shows the structure 140 deployed in a collapsed condition in the loweresophageal sphincter 18, where the abnormal epithelium tissue conditionforms. FIG. 40 shows the structure 140 in an expanded condition,contacting the abnormal epithelium tissue.

[0243] The structure 140 carries an array of surface electrodes 142. Inthe illustrated embodiment, the surface electrodes 142 are carried by anelectrically conductive wire 144, e.g., made from nickel-titanium alloymaterial. The wire 144 extends from the distal end of the catheter tube30 and wraps about the structure 140 in a helical pattern. Theelectrodes 142 are electrically coupled to the wire 144, e.g., by solderor adhesive. Alternatively, the balloon structure 140 can have painted,coated, or otherwise deposited on it solid state circuitry to providethe electrical path and electrodes.

[0244] Expansion of the balloon structure 140 places the surfaceelectrodes 142 in contact with the abnormal epithelium. The applicationof radio frequency energy ohmically heats the tissue surface, causingnecrosis of the abnormal epithelium. The desired effect is the ablationof the mucosal surface layer (about 1 mm to 1.5 mm), without substantialablation of underlying tissue. The structure 140 is then collapsed, andthe operative element 138 is removed.

[0245] Absent chronic exposure to stomach 12 acid due to continuedspontaneous relaxation of the lower esophageal sphincter 18, subsequenthealing of the necrosed surface tissue will restore a normal esophagealepithelium.

[0246] D. Electrode Structures to Minimize Lesion Overlap

[0247] As before described, it is desirable to create one or moresymmetric rings of lesions with enough total volume to sufficientlyshrink the lower esophageal sphincter or cardia.

[0248]FIG. 83 shows a lesion pattern 500 that has demonstrated efficacyin treating GERD. The lesion pattern 500 begins at the Z-line 502, whichmarks the transition between esophageal tissue (which is generally whitein color) and stomach tissue (which is generally pink in color). Thetissue color change at or near the Z-line 502 can be readily visualizedusing an endoscope.

[0249] The lower esophageal sphincter 18 (which is about 4 cm to 5 cm inlength) extends above and below the Z-line 502. The Z-line 502 marks thehigh pressure zone of the lower esophageal sphincter 18. In the regionof the Z-line 502, the physician may encounter an overlap of sphinctermuscle and cardia muscle.

[0250] As FIG. 83 shows, the lesion pattern 500 extends about 2 cm to 3cm from the Z-line 502 into the cardia 20. The pattern 500 comprises ahigh density of lesion rings 504, spaced apart by about 5 mm, with fromfour to sixteen lesions in each ring 504. Five rings 504(1) to 504 (5)are shown in FIG. 83. The uppermost ring 504(1) (at or near the Z-line502) contains eight lesions. The next three rings 504(2) to 504 (4) eachcontains twelve lesions. The lower most ring 504(5) contains eightlesions.

[0251] The lesion pattern 500 formed in this transition region below theZ-line 502 creates, upon healing, an overall desired tightening of thesphincter 18 and adjoining cardia 20 muscle, restoring a normal closurefunction.

[0252] It is also believed that the pattern 500 formed in thistransition region may also create a neurophysiologic effect, as well.The lesion pattern 500 may interrupt infra- and supra-sphincter nerveconduction. The nerve pathway block formed by the lesion pattern 500 maymediate pain due to high pH conditions that accompany GERD and may inother ways contribute to the overall reduction of spontaneous sphincterrelaxation that the procedure provides.

[0253] As before described, rotation or sequential movement ofelectrodes 66 can achieve the desired complex lesion pattern 500.However, in sequentially placing the lesions, overlapping lesions canoccur.

[0254] There are various ways to minimize the incidence of lesionoverlap.

[0255] (i) Full Ring Electrode Structures

[0256] To prevent overlapping lesions, the operative element 36 can,e.g., carry a number of electrodes 66 sufficient to form all the desiredlesions in a given circumferential ring with a single deployment. Forexample, as FIG. 53 illustrates, when the desired number of lesions fora given ring is eight, the operative element 36 carries eight electrodes66. In this arrangement, the electrodes 66 are equally spaced about thecircumference of the balloon structure 72 on eight spines 58. As beforedescribed, each spine 58 preferably includes an interior lumen with aport 98 to convey a cooling liquid like sterile water into contact withthe mucosal surface of the the targeted tissue site.

[0257] The generator 38 can include eight channels to supply treatmentenergy simultaneously to the eight electrodes 66. However, the generator38 that supplies treatment energy simultaneously in four channels tofour electrodes 66 shown, e.g., in FIG. 22, can be readily configured bythe controller 52 to supply treatment energy to the eight electrodes 66shown in FIG. 53.

[0258] (1) Monopolar/Hottest Temperature Control

[0259] In one configuration, pairs of electrodes 66 are shortedtogether, so that each channel simultaneously powers two electrodes in amonopolar mode. For simplicity, the shorted electrodes 66 are preferablylocated on adjacent spines 58, but an adjacent relationship for shortedelectrodes is not essential.

[0260] Each electrode 66 carries a temperature sensor 80, coupled to theI/O device 54 of the controller 52, as previously described. Thecontroller 52 alternatively samples the temperature sensed by thesensors 80 for each shorted pair of electrodes 66. The controller 52selects the hottest sensed temperature to serve as the input to controlthe magnitude of power to both electrodes. Both electrodes receive thesame magnitude of power, as they are shorted together.

[0261] (2) Monopolar/Average Temperature Control

[0262] In one configuration, pairs of electrodes 66 are shortedtogether, as described in the previous configuration, so that eachchannel simultaneously powers two electrodes in a monopolar mode.

[0263] Each electrode 66 carries a temperature sensor 80 and are coupledto the I/O device 54 of the controller 52. In this configuration, thetemperature sensors 80 for each shorted pair of electrodes 66 areconnected in parallel. The controller 52 thus receives as input atemperature that is approximately the average of the temperatures sensedby the sensors 80 for each shorted pair of electrodes 66. The controller52 can include an algorithm to process the input to achieve a weightedaverage. The controller 52 uses this approximate average to control themagnitude of power to both electrodes. As previously stated, bothelectrodes receive the same magnitude of power, as they are shortedtogether.

[0264] (3) Monopolar/Switched Control

[0265] In this configuration, the controller 52 includes a switchelement, which is coupled to each electrode 66 and its associatedtemperature sensor 80 independently. In one position, the switch elementcouples the four channels of the generator 38 to four of the electrodes(Electrode Group A). In another position, the switch element couples thefour channels of the generator 38 to another four of the electrodes(Electrode Group B).

[0266] The electrodes of Group A could be located on one side of theelement 36, and the electrodes of Group B could be located on theopposite side of the element 36. Alternatively, the electrodes 66 ofGroups A and B can be intermingled about the element 36.

[0267] The switch element can switch between Electrode Group A andElectrode Group B, either manually or automatically. The switching canoccur sequentially or in a rapidly interspersed fashion.

[0268] In a sequential mode, Electrode Group A is selected, and thecontroller samples the temperatures sensed by each sensor 80 andindividually controls power to the associated electrode 66 based uponthe sensed temperature. As tissue heating effects occur as a result ofthe application of energy by Electrode Group A, the other ElectrodeGroup B is selected. The controller samples the temperatures sensed byeach sensor 80 and individually controls power to the associatedelectrode 66 based upon the sensed temperature. As tissue heatingeffects occur as a result of the application of energy by ElectrodeGroup B, the other Electrode Group A is selected, and so on. This modemay minimize overheating effects for a given electrode group.

[0269] In an interspersed fashion, the switching between ElectrodeGroups A and B occurs at greater time intervals between the applicationof energy, allowing tissue moisture to return to dessicated tissuebetween applications of energy.

[0270] (4) Bipolar Control

[0271] In this configuration, the controller 52 conditions fourelectrodes 66 to be transmitters (i.e., coupled to the four channels ofthe generator 38) and conditions the other four electrodes to be returns(i.e., coupled to the energy return of the generator 38). Forsimplicity, the transmitter and return electrodes are preferably locatedon adjacent spines 58, but this is not essential.

[0272] In one arrangement, the four returns can be independent, with nocommon ground, so that each channel is a true, independent bipolarcircuit. In another arrangement, the four returns are shorted to providea single, common return.

[0273] For each bipolar channel, the controller 52 samples temperaturessensed by the sensors 80 carried by each electrode 66. The controller 52can average the sensed temperature conditions by each electrode pair.The controller 52 can include an algorithm to process the input toachieve a weighted average. Alternatively, the controller 52 can selectthe maximum temperature condition sensed by each electrode pair forcontrol purposes.

[0274] The electrodes 66 used as return electrodes can be larger thanthe electrodes 66 used to transmit the energy. In this arrangement, thereturn electrodes need not carry temperature sensors, as the hottesttemperature will occur at the smaller energy transmitting electrode.

[0275] (ii) Partial Ring Electrode Structures

[0276] To prevent overlapping lesions, the operative element 36 can,e.g., carry a number of electrodes 66 sufficient to form, in a singledeployment, a partial arcuate segment of the full circumferential ring.For example, as FIG. 54 illustrates, when the desired number of lesionsfor a given ring is eight, the operative element 36 carries fourelectrodes 66 in a closely spaced pattern spanning 135 degrees on fourspines 58.

[0277] In use, the physician deploys the element 36 and creates fourlesions in a partial arcuate segment comprising half of the fullcircumferential ring. The physician then rotates the element 36one-hundred and eighty degrees and creates four lesions in a partialarcuate segment that comprises the other half of the fullcircumferential ring.

[0278] The physician may find that there is less chance of overlappinglesions by sequentially placing four lesions at 180 intervals, thanplacing four lesions at 90 degree intervals, as previously described.

[0279] E. Mechanically Expandable Electrode Structures

[0280]FIGS. 41 and 42 show an operative element 146 suited fordeployment in the lower esophageal sphincter 18, cardia 20, and otherareas of the body.

[0281] In this embodiment, the operative element 146 comprises anexpandable, three-dimensional, mechanical basket 148. As illustrated,the basket 148 includes eight jointed spines 150, although the number ofspines 158 can, of course, vary. The jointed spines 150 are pivotallycarried between a distal hub 152 and a proximal base 154.

[0282] Each jointed spine 150 comprises a body made from inert wire orplastic material. Elastic memory material such as nickel titanium(commercially available as NITINOL™ material) can be used, as canresilient injection molded plastic or stainless steel. In theillustrated embodiment, the jointed spines 150 possess a rectilinearcross sectional shape. However, the cross sectional shape of the spines150 can vary.

[0283] Each jointed spine 150 includes a distal portion 158 and aproximal portion 160 joined by a flexible joint 156. The distal andproximal portions 158 and 160 flex about the joint 156. In theillustrated embodiment, the spine portions 158 and 160 and joint 156 areintegrally formed by molding. In this arrangement, the joint 156comprises a living hinge. Of course, the spine portions 158 and 160 canbe separately manufactured and joined by a mechanical hinge.

[0284] In the illustrated embodiment, a pull wire 162 is attached to thedistal hub 152 of the basket 148. Pulling on the wire 162 (e.g., bymeans of a suitable push-pull control on a handle at the proximal end ofthe catheter tube 30) draws the hub 152 toward the base 154.Alternatively, a push wire joined to the base 154 can advance the base154 toward the hub 152. In either case, movement of the base 154 and hub152 toward each other causes the spines 150 to flex outward about thejoints 156 (as FIG. 42 shows). The basket 148 opens, and its maximumdiameter expands.

[0285] Conversely, movement of the base 154 and hub 152 away from eachother causes the spines 150 to flex inward about the joints 156. Thebasket 148 closes (as FIG. 41 shows), and its maximum diameter decreasesuntil it assumes a fully collapsed condition.

[0286] Each joint 156 carries an electrode 166. The electrode 166 cancomprise an integrally molded part of the spine 150, or it can comprisea separate component that is attached, e,g. by solder or adhesive, tothe spine 150. The electrode material can also be deposited or coatedupon the spine 150.

[0287] When the basket 148 is closed, the electrodes 166 nest within thejoints 156 in a lay flat condition (as FIG. 41 shows), essentiallycoplanar with the distal and proximal portions 158 and 160 of the spines150. As best shown in FIG. 43, as the basket 148 opens, flexure of thespines 150 about the joints 156 progressively swings the electrodes 166outward into a position for penetrating tissue (designated T in FIG.43).

[0288] As FIG. 43 shows, flexure of a given spine 150 about theassociated joint 156 swings the electrode 166 in a path, in which theangle of orientation of the electrode 166 relative to the spineprogressively increases. As the basket 148 opens, the electrode 166 andthe distal portion 158 of the spine 150 become generally aligned in thesame plane. Further expansion increases the radial distance between thebasket axis 164 and distal tip of the electrode 166 (thereby causingtissue penetration), without significantly increasing the swing anglebetween the basket axis 164 and the electrode 166 (thereby preventingtissue tear). During the final stages of basket expansion, the electrode166 moves in virtually a linear path into tissue. It is thus possible todeploy the electrode in tissue simultaneously with opening the basket148.

[0289]FIGS. 44 and 45 show an operative element 168 comprising a springbiased basket 170. In the illustrated embodiment, the distal end of thecatheter tube 30 carries two electrodes 172. A single electrode, or morethan two electrodes, can be carried in the same fashion on the distalend of the catheter tube 30.

[0290] The electrodes 172 are formed from a suitable energy transmittingmaterials, e.g stainless steel. The electrodes 172 have sufficientdistal sharpness and strength to penetrate a desired depth into thesmooth muscle of the esophageal or cardia 20 wall.

[0291] The proximal end of each electrode 172 is coupled to the leafspring 174. The leaf spring 174 normally biases the electrodes 172 in anoutwardly flexed condition facing the proximal end of the catheter tube30 (as FIG. 44 shows).

[0292] An electrode cover 176 is slidably mounted on the distal end ofthe catheter tube 30. A stylet 178 is coupled to the electrode cover176. The stylet 178 is movable axially along the catheter tube 30, e.g.,by a lever on the handle at the proximal end of the catheter tube 30.

[0293] Pulling on the stylet 178 moves the electrode cover 176 over theelectrodes 172 into the position shown in FIG. 45. On this position, thecover 176 encloses the electrodes 172, pulling them inward against thedistal end of the catheter tube 30. Enclosed within the cover 176, theelectrodes 172 are maintained in a low profile condition for passagethrough the esophagus, e.g., through lower esophageal sphincter 18 andinto a position slightly beyond the surface of the cardia 20.

[0294] Pushing on the stylet 178 moves the electrode cover 176 toward adistal-most position beyond the electrodes 172, as shown in FIG. 44.Progressively unconstrained by the cover 176, the electrodes 172 springoutward. The outward spring distance of electrodes 172 depends upon theposition of the cover 176. The electrodes 172 reach their maximum springdistance when the cover 176 reaches its distal-most position, as FIG. 44shows. The distal ends of the electrodes 172 are oriented proximally, topoint, e.,g. toward the cardia 20.

[0295] With the electrodes 172 sprung outward, the physician pullsrearward on the catheter tube 30. The electrodes 172 penetrate thecardia 20. The electrodes apply energy, forming subsurface lesions inthe cardia 20 in the same fashion earlier described. As FIG. 44 shows,the proximal region of each electrode 172 is preferably enclosed by anelectrical insulating material 70, to prevent ohmic heated of themucosal surface of the cardia 20.

[0296] Upon formation of the lesions, the physician can move thecatheter tube 30 forward, to advance the electrodes 172 out of contactwith the cardia 20. By rotating the catheter tube 30, the physician canreorient the electrodes 172. The physician can also adjust the positionof the cover 176 to increase or decrease the diameter of the outwardlyflexed electrodes 172. Pulling rearward on the catheter tube 30 causesthe electrodes to penetrate the cardia 20 in their reoriented and/orresized position. In this way, the physician can form desired ring orrings of lesion patterns, as already described.

[0297] Upon forming the desired lesion pattern, the physician advancesthe electrodes 172 out of contact with the cardia 20. The physicianmoves the cover 176 back over the electrodes 172 (as FIG. 45 shows). Inthis condition, the physician can withdraw the catheter tube 30 andoperative element 168 from the cardia 20 and esophagus 10, completingthe procedure.

[0298] F. Extruded Electrode Support Structures

[0299] FIGS. 63 to 65 show another embodiment of an operative element216 suited for deployment in the lower esophageal sphincter 18, cardia20, and other areas of the body. In this embodiment, the operativeelement 216 comprises an expandable, extruded basket structure 218 (asFIG. 65 shows).

[0300] The structure 218 is first extruded (see FIG. 63) as a tube 224with a co-extruded central interior lumen 220. The tube 224 alsoincludes circumferentially spaced arrays 222 of co-extruded interiorwall lumens. Each array 222 is intended to accommodate an electrode 66and the fluid passages associated with the electrode 66.

[0301] In each array 222, one wall lumen accommodates passage of anelectrode 66 and related wires. Another lumen in the array 222 iscapable of passing fluids used, e.g. to cool the mucosal surface.Another lumen in the array 222 is capable of passing fluids aspiratedfrom the targeted tissue region, if required.

[0302] Once extruded (see FIG. 64), the tube wall is cut to form slits230 between the lumen arrays 222. Proximal and distal ends of the tubeare left without slits 230, forming a proximal base 226 and a distal hub228. Appropriate ports 232 are cut in the tube wall between the slits230 to accommodate passage of the electrodes 66 and fluids through thewall lumens. The base 226 is coupled to the distal end of a cathetertube 236.

[0303] In the illustrated embodiment (see FIG. 65), a pull wire 234passing through the interior lumen 220 is attached to the distal hub228. Pulling on the wire 234 (e.g., by means of a suitable push-pullcontrol on a handle at the proximal end of the catheter tube 236) drawsthe hub 228 toward the base 226 (as FIG. 65 shows). Alternatively, apush wire joined to the base 226 can advance the base 226 toward the hub228.

[0304] In either case, movement of the base 226 and hub 228 toward eachother causes the tube 224 to flex outward between the slits 230,forming, in effect, a spined basket. The extruded basket structure 218opens, and its maximum diameter expands.

[0305] Conversely, movement of the base 226 and hub 228 apart causes thetube 224 to flex inward between the slits 230. The extruded basketstructure 218 closes and assumes a collapsed condition.

[0306] The central co-extruded lumen 220 is sized to accommodate passageof a guide wire or an endoscope, as will be described in greater detaillater.

[0307] G. Cooling and Aspiration

[0308] As previously described with respect to the operative element 36shown, e.g., in FIGS. 5, 7, and 11, it is desirable to cool the mucosalsurface while applying energy to ohmically heat muscle beneath thesurface. To accomplish this objective, the operative element 36 includesa means for applying a cooling liquid like sterile water to mucosaltissue at the targeted tissue region and for aspirating or removing thecooling liquid from the targeted tissue region.

[0309] Various constructions are possible.

[0310] (i) Aspiration Through the Spines

[0311] In the embodiment shown in FIGS. 55 and 56, the spines 58 extendbetween distal and proximal ends 60 and 62 of the element 36, forming abasket 56. Four spines 58 are shown for purpose of illustration. Anexpandable balloon structure 72 is located within the basket 56, asalready described. An inflation tube 204 (see FIG. 56) conveys a mediato expand the structure 72 during use.

[0312] As FIGS. 55 and 56 show, each spine 58 comprises three tubes 186,188, and 190. Each tube 186, 188, and 190 has an interior lumen.

[0313] The first tube 186 includes an electrode exit port 192 (see FIG.56). The electrode 66 passes through the exit port 192 for deployment inthe manner previously described.

[0314] The second tube 188 includes a cooling port 194. The coolingliquid passes through the cooling port 194 into contact with mucosaltissue. The cooling port 194 is preferably situated on the outside(i.e., tissue facing) surface of the spine 58, adjacent the electrodeexit port 192 (see FIG. 56).

[0315] The third tube 190 includes an aspiration port 196. Coolingliquid is aspirated through the port 196. The port 196 is preferablysituated on the inside (i.e. facing away from the tissue) surface of thespine 58.

[0316] Preferable, at least one of the aspiration ports 196 is locatednear the distal end 60 of the element 36, and at least one theaspiration ports 196 is located near the proximal end 62 of the element36. In the illustrated embodiment, two aspiration ports are located nearthe distal end 60, on opposite spines 58 (see FIG. 55). Likewise, twoaspiration ports are located near the proximal end 62, on oppositespines 58 (see FIG. 56). This arrangement provides for efficient removalof liquid from the tissue region.

[0317] The electrodes 66 are commonly coupled to the control lever 198on the handle 28 (see FIG. 57), to which the catheter tube 30 carryingthe element 36 is connected. The lumen of the second tube 188communicates with a port 200 on the handle 28. In use, the port 200 iscoupled to a source of cooling fluid. The lumen of the third tube 190communicates with a port 202 on the handle 28. In use, the port 202 iscoupled to a vacuum source. The inflation tube 204 communicates with aport 206 on the handle 28. The port 206 connects to a source ofinflation media, e.g., air in a syringe.

[0318] (ii) Interior Aspiration Through An Inner Member

[0319] In the alternative embodiment shown in FIG. 58A, the spines 58(eight are shown for purpose of illustration) each comprises at leasttwo tubes 186 and 188. In FIG. 58A, the inflation tube 204 extendsthrough the expandable balloon structure 72, between the distal andproximal ends 60 and 62 of the element 36. Inflation ports 208communicate with a lumen within the tube 204 to convey the expansionmedia into the structure 72.

[0320] The first tube 186 includes the electrode exit port 192, throughwhich the electrode 66 passes. The second tube 188 includes the outsidefacing cooling port 194, for passing cooling liquid into contact withmucosal tissue.

[0321] At least one aspiration port 196 communicates with a second lumenin the inflation tube 204. In the illustrated embodiment, two aspirationports 196 are provided, one near the distal end 60 of the element 36,and the other near the proximal end 62 of the element 36.

[0322] The element 36 shown in FIG. 58A can be coupled to the handle 28shown in the FIG. 57 to establish communication between the tubes 188and 204 in the manner already described.

[0323] In an alternative embodiment (shown in phantom lines in FIG.58A), a sponge-like, liquid retaining material 320 can be applied abouteach spine 58 over the electrode exit port 192 the cooling port 194. Theelectrode 66 passes through the spongy material 320. Cooling liquidpassing through the cooling port 194 is absorbed and retained by thespongy material 320. The spongy material 320 keeps the cooling liquid incontact with mucosal tissue at a localized position surrounding theelectrode 66. By absorbing and retaining the flow of cooling liquid, thespongy material 320 also minimizes the aspiration requirements. Thepresence of the spongy material 320 to absorb and retain cooling liquidalso reduces the flow rate and volume of cooling liquid required to coolmucosal tissue, and could eliminate the need for aspiration altogether.

[0324] In another alternative embodiment, as shown in FIG. 58B, thespines 58 (eight are shown for purpose of illustration) each comprises asingle tube 186, which includes the electrode exit port 192, throughwhich includes the electrode exit port 192, through which the electrode66 passes. As in FIG. 58A, the inflation tube 204 in FIG. 58B extendsthrough the expandable balloon structure 72. Inflation ports 208communicate with a lumen within the tube 204 to convey the expansionmedia into the structure 72.

[0325] In this embodiment, the expansion medium comprises the coolingliquid. A pump conveys the cooling liquid into the structure 72. Fillingthe structure 72, the cooling liquid causes expansion. The structure 72further includes one or more small pin holes PH near each electrode 66.The cooling liquid “weeps” through the pin holes PH, as the pumpcontinuously conveys cooling liquid into the structure 72. The coolingliquid contacts and cools tissue in the manner previously described.

[0326] As in FIG. 58A, at least one aspiration port 196 communicateswith a second lumen in the inflation tube 204 to convey the coolingliquid from the treatment site. In FIG. 58B, two aspiration ports 196are provided, one near the distal end 60 of the element 36, and theother near the proximal end 62 of the element 36.

[0327] (iii) Tip Aspiration/Guide Wire

[0328] In the alternative embodiment shown in FIG. 59, the spines 58(four are shown for purpose of illustration) each comprises at least twotubes 186 and 188. Like the embodiment shown in FIG. 58, the inflationtube 204 in FIG. 59 extends through the expandable balloon structure 72,between the distal and proximal ends 60 and 62 of the element 36.Inflation ports 208 communicate with a lumen within the tube 204 toconvey the expansion media into the structure 72.

[0329] The first tube 186 includes the electrode exit port 192, throughwhich the electrode 66 passes. The second tube 188 includes the outsidefacing cooling port 194, for passing cooling liquid into contact withmucosal tissue.

[0330] In the embodiment shown in FIG. 59, the distal end 60 of theelement 36 includes an aspiration port 196, which communicates with asecond lumen in the inflation tube 204.

[0331] The element 36 shown in FIG. 58 can be coupled to the handle 28shown in the FIG. 57 to establish communication between the tubes 188and 204 in the manner already described.

[0332] In the embodiment shown in FIG. 59, the lumen in the inflationtube 204 used for aspiration can be alternatively used to pass a guidewire 210, as FIG. 60 shows. The guide wire 210 is introduced through theaspiration port 202 on the handle 28 (as FIG. 61 shows) Use of a guidewire 210 can obviate the need for the introducer 32 previously describedand shown in FIG. 9, which may in certain individuals cause discomfort.In use, the physician passes the small diameter guide wire 210 throughthe patient's mouth and pharynx, and into the esophagus 10 to thetargeted site of the lower esophageal sphincter or cardia. The physiciancan next pass the operative element 36 (see FIG. 60) over the guide wire210 into position. The physician can also deploy an endoscope next tothe guide wire 210 for viewing the targeted site and operative element36.

[0333] Use of the guide wire 210 also makes possible quick exchanges ofendoscope and operative element 36 over the same guide wire 210. In thisarrangement, the guide wire 210 can serve to guide the endoscope andoperative element 36 to the targeted site in quick succession.

[0334] G. Vacuum-Assisted Stabilization of Mucosal Tissue

[0335] As FIG. 66 shows, mucosal tissue MT normally lays in folds in thearea of the lower esophageal sphincter 18 and cardia 20, presenting afully or at least partially closed closed path. In the precedingembodiments, various expandable structures are deployed to dilate themucosal tissue MT for treatment. When dilated, the mucosal tissue foldsexpand and become smooth, to present a more uniform surface forsubmucosal penetration of the electrodes 66. The dilation mediatesagainst the possibility that an electrode 66, when deployed, might slideinto a mucosal tissue fold and not penetrate the underlying sphinctermuscle.

[0336] (i) Rotational Deployment of Electrodes

[0337] FIGS. 67 to 69 show an alternative treatment device 238 suitedfor deployment in the lower esophageal sphincter 18, cardia 20, andother regions of the body to direct electrodes 66 into targetedsubmucosal tissue regions.

[0338] The device 238 includes a handle 248 (see FIG. 67) that carries aflexible catheter tube 242. The distal end of the catheter tube 242carries an operative element 244.

[0339] The operative element 244 includes a proximal balloon 246 and adistal balloon 248. The balloons 246 and 248 are coupled to an expansionmedia by a port 276 on the handle 240.

[0340] An electrode carrier 250 is located between the balloons 246 and248. As FIGS. 67 and 68 show, the carrier 250 includes a generallycylindrical housing 252 with an exterior wall 268. The housing 252includes a series of circumferentially spaced electrode pods 256. Eachpod 256 extends radially outward of the wall 268 of housing 252.

[0341] As FIGS. 68 and 69 show, each pod 256 includes an interiorelectrode guide bore 258. The guide bore 258 extends in a curved paththrough the pod 256 and terminates with an electrode port 262 spacedoutward from the wall of the housing.

[0342] The housing 252 also includes a series of suction ports 260 (seeFIGS. 68 and 69). Each suction port 260 is located flush with thehousing wall 268 close to an electrode port 262. The suction ports 260are coupled to a source of negative pressure through a port 274 on thehandle 240.

[0343] A driver disk 254 is mounted for rotation within the housing 252.Electrodes 264 are pivotally coupled to the driver disk 254 on pins 266arranged in an equally circumferentially spaced pattern.

[0344] The electrodes 264 can be formed from various energy transmittingmaterials, e.g., 304 stainless steel. The electrodes 264 are coupled tothe generator 38, preferable through the controller 52.

[0345] The electrodes 264 have sufficient distal sharpness and strengthto penetrate a desired depth into the smooth muscle of the esophageal orcardia 20 apply energy from the generator 38.

[0346] As previously described with respect to other embodiments, anelectrical insulating material 278 (see FIGS. 68 and 69) is coated aboutthe proximal end of each electrode 264. When the distal end of theelectrode 264 penetrating the smooth muscle of the esophageal sphincter18 or cardia 20 transmits radio frequency energy, the material 278insulates the mucosal surface of the esophagus 10 or cardia 20 fromdirect exposure to the radio frequency energy to prevent thermal damageto the mucosal surface. As previously described, the mucosal surface canalso be actively cooled during application of radio frequency energy, tofurther protect the mucosal surface from thermal damage.

[0347] Each electrode 264 is biased with a bend, to pass from the pin266 in an arcuate path through the electrode guide bore 258 in theassociated pod 256. Rotation of the driver disk 254 in one direction(which is clockwise in FIG. 68) moves the electrodes 264 through thebores 258 outward of the carrier 250 (as FIG. 69 shows). Oppositerotation of the driver disk 254 (which is counterclockwise in FIG. 68)moves the electrodes 264 through the bores 258 inward into the carrier250 (as FIGS. 67 and 68 show).

[0348] A drive shaft 270 is coupled to the driver disk 254 to affectclockwise and counterclockwise rotation of the disk 254. A control knob272 on the handle 240 (see FIG. 67) is coupled to the drive shaft 254 toextend and retract the electrodes 264.

[0349] In use, the carrier 250 is located at the desired treatment site,e.g., in the region of the lower esophageal sphincter 18. The balloons246 and 248 are expanded to seal the esophagus in the region between theballoons 246 and 248.

[0350] A vacuum is then applied through the suction ports 260. Thevacuum evacuates air and fluid from the area of the esophageal lumensurrounding the carrier 250. This will cause the surrounding mucosaltissue to be drawn inward against the wall 268 of the housing 252 (seeFIG. 69), to conform and be pulled tightly against the pods 256.

[0351] Applying a vacuum to draw mucosal tissue inward against the pods256 causes the tissue to present a surface nearly perpendicular to theelectrode ports 262 (see FIG. 69). Operation of the driver disk 254moves the electrodes 264 through the ports 262, in a direct path throughmucosal tissue and into the underlying sphincter muscle. Due to thedirect, essentially perpendicular angle of pentration, the electrode 264reaches the desired depth in a short distance (e.g., less than 3 mm),minimizing the amount of insulating material 278 required.

[0352] The application of vacuum to draw mucosal tissue against the pods256 also prevents movement of the esophagus while the electrodes 264penetrate tissue. The counter force of the vacuum resists tissuemovement in the direction of electrode penetration. The vacuum anchorsthe surrounding tissue and mediates against the “tenting” of tissueduring electrode penetration. Without tenting, the electrode 264penetrates mucosal tissue fully, to obtain a desired depth ofpenetration.

[0353] (ii) Straight Deployment of Electrodes

[0354]FIGS. 70 and 71 show another alternative treatment device 280suited for deployment in the lower esophageal sphincter 18, cardia 20,and other regions of the body to direct electrodes 66 into targetedsubmucosal tissue regions.

[0355] The device 280 includes a handle 282 (see FIG. 70) that carries aflexible catheter tube 284. The distal end of the catheter tube 284carries an operative element 286.

[0356] The operative element 286 includes a proximal balloon 288 and adistal balloon 290. The balloons 288 and 290 are coupled to an expansionmedia by a port 292 on the handle 284.

[0357] An electrode carrier 294 is located between the balloons 246 and248. The carrier 294 includes a generally cylindrical housing 296 withan exterior wall 298 (see FIG. 71). The housing 296 includes a series ofcircumferentially and axially spaced recesses 300 in the wall 298 (bestshown in FIG. 70).

[0358] As FIG. 71 shows, an electrode guide bore 302 extends through thewall 298 and terminates with an electrode port 304 in each recess 300.The axis of each guide bore 302 is generally parallel to the plane ofthe corresponding recess 300.

[0359] The housing 296 also includes a series of suction ports 306, onein each recess 300. The suction ports 306 are coupled to a source ofnegative pressure through a port 308 on the handle 282.

[0360] An electrode mount 310 (see FIG. 71) is mounted for axialmovement within the housing 296. Electrodes 312 are pivotally coupled tothe mount 310.

[0361] The electrodes 312 can be formed from various energy transmittingmaterials, e.g., 304 stainless steel. The electrodes 312 are coupled tothe generator 38, preferable through the controller 52.

[0362] The electrodes 312 have sufficient distal sharpness and strengthto penetrate a desired depth into the smooth muscle of the esophageal orcardia 20 apply energy from the generator 38. As previously describedwith respect to other embodiments, an electrical insulating material 314(see FIG. 71) is coated about the proximal end of each electrode 312.

[0363] Each electrode 312 is generally straight, to pass from the mount310 through the electrode guide bore 302. Axial movement of the mount310 toward the guide bores 302 extends the electrodes 312 outward intothe recesses 300, as FIG. 71 shows. Opposite axial movement of the mount310 withdraws the electrodes 312 through the bores 302 inward fromrecesses 300 (as FIG. 70 shows).

[0364] A stylet 316 (see FIG. 71) is coupled to the mount 310 to affectaxial movement of the mount 310. A push-pull control knob 318 on thehandle 282 is coupled to the stylet 316 to extend and retract theelectrodes 264. Alternatively, a spring loaded mechanism can be used to“fire” the mount 310 to deploy the electrodes 312.

[0365] In use, the carrier 294 is located at the desired treatment site,e.g., in the region of the lower esophageal sphincter. The balloons 288and 290 are expanded to seal the esophagus in the region between theballoons 288 and 290.

[0366] A vacuum is then applied through the suction ports 292. Thevacuum evacuates air and fluid from the area of the esophageal lumensurrounding the carrier 294. This will cause the surrounding mucosaltissue to be drawn inward into the recesses, to conform and be pulledtightly against the recesses 300, as FIG. 71 shows.

[0367] Applying a vacuum to draw mucosal tissue inward into the recesses300 causes the tissue to present a surface nearly perpendicular to theelectrode ports 304, as FIG. 71 shows. Operation of the mount 310 movesthe electrodes 312 through the ports 304, in a path through mucosaltissue and into the underlying sphincter muscle that is generallyparallel to the axis of the esophageal lumen.

[0368] In the same manner described with regard to the precedingembodiment, the application of vacuum to draw mucosal tissue into therecesses 300 also anchors the carrier 294 in the esophagus while theelectrodes 312 penetrate tissue. Ribs and the like can also be providedin the recesses 300 or along the wall 298 of the housing 296 to enhancethe tissue anchoring effect. The counter force of the vacuum resiststissue movement in the direction of electrode penetration. The vacuumanchors the surrounding tissue and mediates against the “tenting” oftissue during electrode penetration. The electrodes 312 penetratesmucosal tissue fully, to obtain a desired depth of penetration.

[0369] H. Visualization

[0370] Visualization of the targeted tissue site before, during, andafter lesion formation is desirable.

[0371] (i) Endoscopy

[0372] As earlier shown in FIGS. 9 and 10, a separately deployedendoscope 84, carried by a flexible catheter tube 86, is used tovisualize the targeted site. In this embodiment, the operative element36 is deployed separately, by means of a separate catheter tube 30.

[0373] In an alternative embodiment (shown in FIGS. 46 to 49), atreatment device 26 is deployed over the same catheter tube 86 thatcarries the endoscope 84. In effect, this arrangement uses the flexiblecatheter tube 86 of the endoscope 84 as a guide wire.

[0374] In this embodiment, the treatment device 26 can carry anysuitable operative element (which, for this reason, is genericallydesignated OE in FIGS. 46 to 49). As FIGS. 47 and 47 show, the cathetertube 30 passes through and beyond the interior of the operative elementOE. The catheter tube 30 further includes a central lumen 180, which issized to accommodate passage of the flexible catheter tube 86 carryingthe endoscope 84.

[0375] As shown in FIG. 48, once the endoscope 84 is deployed in themanner shown in FIGS. 9 and 10, the operative element OE can be passedover the catheter tube 86 to the targeted tissue region. In FIG. 48, thetargeted region is shown to be the cardia 20.

[0376] In use, the endoscope 86 extends distally beyond the operativeelement OE. By retroflexing the endoscope 86, as FIGS. 48 and 49 show,the physician can continuously monitor the placement of the operativeelement OE, the extension of the electrodes 66, and the other steps ofthe lesion formation process already described.

[0377] When the operative element OE includes the expandable balloonstructure 72 (see FIGS. 50 and 51), the structure 72 and the extent ofthe catheter tube 30 passing through it, can be formed of a materialthat is transparent to visible light. In this arrangement, the physiciancan retract the endoscope 84 into expandable structure 72 (as FIG. 51shows). The physician can then monitor the manipulation of the operativeelement OE and other steps in the lesion formation process from withinthe balloon structure 72. Any portion of the catheter tube 30 can bemade from a transparent material, so the physician can visualize atother locations along its length.

[0378] As FIG. 52 shows, the mechanically expanded basket 148 (shownearlier in FIGS. 41 and 42) can be likewise be modified for deploymentover the catheter tube 86 that carries the flexible endoscope 84. Inthis arrangement, the interior lumen 180 extends through the cathetertube 30, the basket 148, and beyond the basket hub 152. The lumen 180 issized to accommodate passage of the endoscope 84.

[0379] In another embodiment (see FIG. 62), the endoscope 84 itself caninclude an interior lumen 212. A catheter tube 214, like that previouslyshown in FIG. 38, can be sized to be passed through the interior lumen212 of the endoscope 84, to deploy a mono-polar electrode 66 (or abipolar pair of electrodes) into penetrating contact with a desiredtissue region. As FIG. 62 shows, the electrode 66 can carry a limitcollar 121 to resist advancement of the electrode 66 beyond a desiredpenetration depth.

[0380] In another embodiment, to locate the site of lower esophagealsphincter 18 or cardia 20, a rigid endoscope can be deployed through theesophagus of an anesthetized patient. Any operative element OE can bedeployed at the end of a catheter tube to the site identified by rigidendoscopy, to perform the treatment as described. In this arrangement,the catheter tube on which the operative element is deployed need not beflexible. With an anesthetized patient, the catheter tube that carriesthe operative element OE can be rigid.

[0381] With rigid endoscopy, the catheter tube can be deployedseparately from the endoscope. Alternatively, the catheter tube caninclude an interior lumen sized to pass over the rigid endoscope.

[0382] (ii) Fluoroscopy

[0383] Fluoroscopy can also be used to visual the deployment of theoperative element OE. In this arrangement, the operative element OE ismodified to carry one or more radiopaque markers 182 (as FIG. 24 shows)at one or more identifiable locations, e.g, at the distal hub 60, orproximal base 62, or both locations.

[0384] With a patient lying on her left side upon a fluoroscopy table,the physician can track movement of the radiopaque markers 182 tomonitor movement and deployment of the operative element OE. Inaddition, the physician can use endoscopic visualization, as previouslydescribed.

[0385] (iii) Ultrasound

[0386] The catheter tube can carry an ultrasound transducer 184 (as FIG.21 shows) adjacent the proximal or distal end of the operative elementOE. The physician can observe the transesophageal echo as a real timeimage, as the operative element OE is advanced toward the loweresophageal sphincter 18. The real time image reflects the thickness ofthe esophageal wall.

[0387] Loss of the transesophageal echo marks the passage of theultrasound transducer 184 beyond lower esophageal sphincter 18 into thestomach 12. The physician pulls back on the catheter tube 30, until thetransesophageal echo is restored, thereby marking the situs of the loweresophageal sphincter 18.

[0388] With the position of the sphincter localized, the physician canproceed to expand the structure 72, deploy the electrodes 66, andperform the steps of procedure as already described. Changes in thetransesophageal echo as the procedure progresses allows the physician tovisualize lesion formation on a real time basis.

[0389] I. The Graphical User Interface (GUI)

[0390] In the illustrated embodiment (see FIGS. 72A and 72B), the radiofrequency generator 38, the controller 52 with I/O device 54, and thefluid delivery apparatus 44 (for the delivery of cooling liquid) areintegrated within a single housing 400.

[0391] The I/O device 54 includes input connectors 402, 404, and 406.The connector 402 accepts an electrical connector 408 coupled to a giventreatment device TD. The connector 404 accepts an electrical connector410 coupled to a patch electrode 412 (for mono-polar operation). Theconnector 406 accepts an pneumatic connector 414 coupled to aconventional foot pedal 416. These connectors 402, 404, and 406 couplethese external devices to the controller 52. The I/O device 54 alsocouples the controller 54 to an array of membrane keypads 422 and otherindicator lights on the housing 400 (see FIG. 73), for entering andindicating parameters governing the operation of the controller 52.

[0392] The I/O device 54 also couples the controller 52 to a displaymicroprocessor 474, as FIG. 82 shows. In the illustrated embodiment, themicroprocessor 474 comprises, e.g., a dedicated Pentium®-based centralprocessing unit. The controller 52 transmits data to the microprocessor474, and the microprocessor 474 acknowledges correct receipt of the dataand formats the data for meaningful display to the physician. In theillustrated embodiment, the dedicated display microprocessor 474 exertsno control over the controller 52.

[0393] In the illustrated embodiment, the controller 52 comprises an68HC11 processor having an imbedded operating system. Alternatively, thecontroller 52 can comprise another style of processor, and the operatingsystem can reside as process software on a hard drive coupled to theCPU, which is down loaded to the CPU during system initialization andstartup.

[0394] The display microprocessor 474 is coupled to a graphics displaymonitor 420. The controller 52 implements through the displaymicroprocessor 474 a graphical user interface, or GUI 424, which isdisplayed on the display monitor 420. The GUI 424 can be realized, e.g.,as a “C” language program implemented by the microprocessor 474 usingthe MS WINDOWS™ or NT application and the standard WINDOWS 32 APIcontrols, e.g., as provided by the WINDOWS™ Development Kit, along withconventional graphics software disclosed in public literature.

[0395] The display microprocessor 474 is also itself coupled to a datastorage module or floppy disk drive 426. The display microprocessor 474can also be coupled to a keyboard, printer, and include one or moreparallel port links and one or more conventional serial RS-232C portlinks or Ethernet™ communication links.

[0396] The fluid delivery apparatus 44 comprises an integrated, selfpriming peristaltic pump rotor 428 with a tube loading mechanism, whichare carried on a side panel of the housing 400. Other types ofnon-invasive pumping mechanisms can be used, e.g., a syringe pump, ashuttle pump, or a diaphragm pump.

[0397] In the illustrated embodiment, the fluid delivery apparatus 44 iscoupled to the I/O device 54 via a pump interface 476. The pumpinterface 476 includes imbedded control algorithms that monitoroperation of the pump rotor 428.

[0398] For example, the pump interface 476 can monitor the delivery ofelectrical current to the pump rotor 428, to assure that the rotor 428is operating to achieve a desired flow rate or range of flow ratesduring use, or, upon shut down, the rotor 428 has stopped rotation. Anoptical encoder or magnetic Halls effect monitor can be used for thesame purpose.

[0399] Alternatively, a flow rate transducer or pressure transducer, orboth, coupled to the pump interface 476, can be placed in line along thepump tubing, or in the treatment device TD itself, to monitor flow rate.

[0400] Flow rate information acquired from any one of these monitoringdevices can also be applied in a closed loop control algorithm executedby the controller 52, to control operation of the pump rotor 428. Thealgorithm can apply proportional, integral, or derivative analysis, or acombination thereof, to control operation of the pump rotor 428.

[0401] In the illustrated embodiment, it is anticipated that thephysician will rely upon the vacuum source typically present in thephysician's suite as the aspiration apparatus 46. However, it should beappreciated that the device 400 can readily integrate the aspirationapparatus 46 by selectively reversing the flow direction of the pumprotor 428 (thereby creating a negative pressure) or by including anadditional dedicated pump rotor or equivalent pumping mechanism toperform the aspiration function.

[0402] In the illustrated embodiment, the integrated generator 38 hasfour independent radio frequency channels. Each channel is capable ofsupplying up to 15 watts of radio frequency energy with a sinusoidalwaveform at 460 kHz. As before explained, the four channels of thegenerator 38 can operate four electrodes in either a monopolar orbipolar mode. As also explained earlier, the four channels can also beconfigured to operate eight electrodes either in a monopolar mode or abipolar mode.

[0403] The integrated controller 52 receives two temperaturemeasurements through the I/O device 54 for each channel, one from thetip of each electrode on the treatment device TD, and one from tissuesurrounding the electrode. The controller 52 can regulate power to theelectrodes in a close-loop based upon the sensed tip temperature, or thesensed tissue temperature, or both, to achieve and maintain a targetedtip tissue temperature at each electrode. The controller 52 can alsoregulate power to the pump rotor 428 in a closed-loop based upon thesensed tip temperature, or the sensed tissue temperature, or both, toachieve an maintain a targeted tissue temperature at each electrode.Alternatively, or in combination, the physician can manually adjust thepower level or pump speed based upon a visual display of the sensed tipand tissue temperatures.

[0404] As FIG. 73 best shows, the membrane keypads 422 and otherindicators on the front panel of the device 400 show the variousoperational parameters and operating states and allow adjustments to bemade. In the illustrated embodiment, as shown in FIG. 73, the keypads422 and indicators include:

[0405] 1. Standby/Ready Button 430, which allows switching from one modeof operation to another, as will be described later.

[0406] 2. Standby/Ready Indicator 432, which displays a green lightafter the device 400 passes a self test upon start up.

[0407] 3. RF On Indicator 434, which displays a blue light when radiofrequency energy is being delivered.

[0408] 4. Fault Indicator 436, which displays a red light when aninternal error has been detected. No radio frequency energy can bedelivered when the Fault Indicator 436 is illuminated.

[0409] 5. Target Duration Keys 438, which allow increases and decreasesin the target power duration at the start or during the course of aprocedure.

[0410] 6. Target Temperature Keys 440, which allow increases anddecreases in the target temperature at the start or during the course ofa procedure.

[0411] 7. Maximum Power Keys 442, which allow increases and decreases inthe maximum power setting at the start or during the course of aprocedure.

[0412] 8. Channel Selection Keys 444, which allow selection of any orall power channels.

[0413] 9. Coagulation Level Keys 446, which manually increases anddecreases the magnitude of the indicated depth of insertion of theelectrodes within the esophagus. This depth is determined, e.g., byvisually gauging the measured markings along the length of the cathetertube of the treatment device TD, as previously described. Alternatively,the coagulation level can be automatically detected by, e.g., placingoptical, mechanical, or magnetic sensors on the mouth piece 82, whichdetect and differentiate among the measured markings along the cathetertube of the treatment device TD to read the magnitude of the depth ofinsertion.

[0414] 10. Flow Rate and Priming Keys 448, which allow for selection ofthree internally calibrated flow rates, low (e.g., 15 ml/min), medium(e.g., 30 ml/min), and high (e.g., 45 ml/min). Pressing and holding the“Up” key activates the pump at a high flow rate for priming, overrulingthe other flow rates until the “Up” key is released.

[0415] In the illustrated embodiment, the graphics display monitor 420comprises an active matrix LCD display screen located between themembrane keypads 422 and other indicators on the front panel. The GUI424 is implemented by showing on the monitor 420 basic screen displays.In the illustrated embodiment, these displays signify four differentoperating modes: Start-Up, Standby, Ready, RF-On, and Pause.

[0416] (i) Start Up

[0417] Upon boot-up of the CPU, the operating system implements the GUI424. The GUI 424 displays an appropriate start-up logo and title image(not shown), while the controller 52 performs a self-test. A movinghorizontal bar or the like can be displayed with the title image toindicate the time remaining to complete the start-up operation.

[0418] (ii) Standby

[0419] Upon completion of the start-up operation, the Standby screen isdisplayed, as shown in FIG. 74. No radio frequency energy can bedelivered while the Standby screen is displayed.

[0420] There are various icons common to the Standby, Ready, RF-On, andPause screens.

[0421] The Screen Icon 450 is an icon in the left hand corner of themonitor 420, which indicates the operating condition of the treatmentdevice TD and its position inside or outside the esophagus. In FIG. 74,the treatment device TD is shown to be disconnected and outside theesophagus. Pressing the “Up” priming key 448, to cause cooling liquid toflow through the treatment device TD, causes an animated priming streamPS to be displayed along the treatment device TD in the icon, as FIG. 73shows. The animated priming stream PS is displayed in the Screen Icon450 whenever the pump rotor 428 is operating to indicate the supply ofcooling fluid through the treatment TD.

[0422] There are also parameter icons designating target duration 452,target temperature 454, maximum power 456, channel selection 458,coagulation level 460, and flow rate/priming 462. These icons arealigned with, respectively, the corresponding Target Duration Keys 438,Target Temperature Keys 440, Maximum Power Keys 442, Channel SelectionKeys 444, Coagulation Level Keys 446, and Flow Rate and Priming Keys448. The icons 452 to 462 indicate current selected parameter values.The flow rate/priming icon 462 shows the selected pump speed byhighlighting a single droplet image (low speed), a double droplet image(medium speed), and a triple droplet image (high speed).

[0423] There is also a floppy disk icon 464 that is normally dimmed,along with the coagulation level icon 460, until a floppy disk isinserted in the drive 426. When a floppy disk is inserted in the drive426, the icons 460 and 464 are illuminated (see FIG. 73), and data issaved automatically after each application of radio frequency energy (aswill be described later).

[0424] There is also an Electrode Icon 466. The Electrode Icon 466comprises an idealized graphical image, which spatially models theparticular multiple electrode geometry of the treatment device TDselected to be deployed in the esophagus. As FIG. 74 shows, fourelectrodes are shown in the graphic image of the Icon 466, which arealso spaced apart by 90 degrees. This graphic image is intended toindicate that the selected treatment device TD has the geometry of thefour-electrode configuration shown, e.g., in FIG. 5.

[0425] For each electrode, the Icon 466 presents in a spatial displaythe magnitude of tip temperature as actually sensed (in outside box El)and the magnitude of tissue temperatures as actually sensed (in insidebox B2). Until a treatment device TD is connected, two dashes appear inthe boxes B1 and B2. The existence of a faulty electrode in thetreatment device will also lead to the same display.

[0426] The controller 52 prohibits advancement to the Ready screen untilnumeric values register in the boxes B1 and B2, as FIG. 75 shows. Thedisplay of numeric values indicate a functional treatment device TD.

[0427] No boxes B1 or B2 will appear in the Icon 466 for a givenelectrode if the corresponding electrode/channel has been disabled usingthe Channel Selection Keys 444, as FIG. 76 shows. In the illustratedembodiment, the physician is able to manually select or deselectindividual electrodes using the Selection Keys 444 in the Standby orReady Modes, but not in the RF-On Mode. However, the controller 52 canbe configured to allow electrode selection while in the RF-On Mode, ifdesired.

[0428] While in the Standby Mode, the physician connects the treatmentdevice TD to the device 400. The physician couples the source of coolingliquid to the appropriate port on the handle of the device TD (aspreviously described) and loads the tubing leading from the source ofcooling liquid (e.g., a bag containing sterile water) in the pump rotor428. The physician also couples the aspiration source to the appropriateport on the handle of the treatment device TD (as also alreadydescribed). The physician also couples the patch electrode 412 and footpedal 416. The physician can now deploy the treatment device TD to thetargeted tissue region in the esophagus, in the manners previouslydescribed. The physician extends the electrodes through mucosal tissueand into underlying smooth muscle.

[0429] Once the treatment device TD is located at the desired locationand the electrodes are deployed, the physician presses the Standby/ReadyButton 430 to advance the device 400 from Standby to Ready Mode.

[0430] (iii) Ready

[0431] In the Ready Mode, the controller 52 commands the generator 38 toapply bursts of low level radio frequency energy through each electrodeselected for operation. Based upon the transmission of these low levelbursts of energy by each electrode, the controller 52 derives a localimpedance value for each electrode. The impedance value indicateswhether or nor the given electrode is in desired contact withsubmucosal, smooth muscle tissue. The use of impedance measurements forthis purpose has been previously explained.

[0432] As FIG. 77 shows, the Ready screen updates the Screen Icon 450 toindicate that the treatment device TD is connected and deployed in thepatient's esophagus. The Ready screen also intermittently blinks the RFOn Indicator 434 to indicate that bursts of radio frequency energy arebeing applied by the electrodes. The Ready screen also updates theElectrode Icon 466 to spatially display in the inside and outside boxesB1 and B2 the actual sensed temperature conditions. The Ready screenalso adds a further outside box B3 to spatially display the derivedimpedance value for each electrode.

[0433] On the Ready screen, instantaneous, sensed temperature readingsfrom the tip electrode and tissue surface, as well as impedance values,are continuously displayed in spatial relation to the electrodes theboxes B1, B2, and B3 in the Electrode Icon 466. An “acceptable” colorindicator (e.g., green) is also displayed in the background of box B1 aslong as the tip temperature reading is within the desiredpre-established temperature range (e.g., 15 to 120° C.). However, if thetip temperature reading is outside the desired range, the colorindicator changes to an “undesirable” color indicator (e.g., to white),and two dashes appear in box B1 instead of numeric values.

[0434] The controller 52 prevents the application of radio frequencyenergy if any temperature reading is outside a selected range (e.g., 15to 120 degrees C.).

[0435] The physician selects the “Up” key of the Flow Rate and PrimingKeys 448 to operate the pump rotor 428 to prime the treatment device TDwith cooling fluid. An animated droplet stream PS is displayed along thetreatment device TD in the Icon 450, in the manner shown in FIG. 75, toindicate the delivery of cooling liquid by the pump rotor 428.

[0436] By touching the Target Duration Keys 438, the Target TemperatureKeys 440, the Maximum Power Keys 442, the Channel Selection Keys 444,the Coagulation Level Keys 446, and the Flow Rate and Priming Keys 448,the physician can affect changes to the parameter values for theintended procedure. The controller 52 automatically adjusts to takethese values into account in its control algorithms. The correspondingtarget duration icon 452, target temperature icon 454, maximum powericon 456, channel selection icon 458, coagulation level icon 460, andflow rate/priming icon 462 change accordingly to indicate the currentselected parameter values.

[0437] When the physician is ready to apply energy to the targetedtissue region, the physician presses the foot pedal 416. In response,the device 400 advances from Ready to RF-On Mode, provided that allsensed temperatures are within the selected range. (iv) RF-On When thefoot pedal 416 is pressed, the controller 52 activates the pump rotor428. Cooling liquid is conveyed through the treatment device TD intocontact with mucosal tissue at the targeted site. At the same time,cooling liquid is aspirated from the treatment device TD in an openloop. During a predetermined, preliminary time period (e.g. 2 to 5seconds) while the flow of cooling liquid is established at the site,the controller 52 prevents the application of radio frequency energy.

[0438] After the preliminary time period, the controller 52 appliesradio frequency energy through the electrodes. The RF-On screen, shownin FIG. 79, is displayed.

[0439] The RF-On screen displays the Screen Icon 450, indicate that thetreatment device TD is connected and deployed in the patient'sesophagus. The flow drop animation PS appears, indicating that coolingis taking place. A flashing radio wave animation RW also appears,indicating that radio frequency energy is being applied. The RF OnIndicator 434 is also continuously illuminated to indicate that radiofrequency energy is being applied by the electrodes.

[0440] The RF-On screen also updates the Electrode Icon 466 to displayin the box B1 the actual sensed tip temperature conditions. The RF-Onscreen also displays the derived impedance value for each electrode inthe boxes B3.

[0441] Unlike the Ready or Standby screens, the surface temperature isno longer displayed in a numerical format in a box B2. Instead, a circleC1 is displayed, which is color coded to indicate whether the surfacetemperature is less than the prescribed maximum (e.g., 45 degrees C.).If the surface temperature is below the prescribed maximum, the circleis colored an “acceptable” color, e.g., green. If the surfacetemperature is exceeds the prescribed maximum, the color of the circlechanges to an “not acceptable” color, e.g., to red.

[0442] Likewise, in addition to displaying numeric values, the boxes B1and B3 are also color coded to indicate compliance with prescribedlimits. If the tip temperature is below the prescribed maximum (e.g.,100 degrees C.), the box B1 is colored, e.g., green. If the tiptemperature is exceeds the prescribed maximum, the box border thickensand the color of the box B1 changes, e.g., to red. If the impedance iswithin prescribed bounds (e.g., between 25 ohms and 1000 ohms), the boxB3 is colored, e.g., grey. If the impedance is outside the prescribedbounds, the box border thickens and the color of the box B3 changes,e.g., to red.

[0443] If desired, the Electrode Icon 466 can also display in a box orcircle the power being applied to each electrode in spatial relation tothe idealized image.

[0444] The RF-On screen displays the target duration icon 452, targettemperature icon 454, maximum power icon 456, channel selection icon458, coagulation level icon 460, and flow rate/priming icon 462,indicating the current selected parameter values. The physician canalter the target duration or target temperature or maximum power andpump flow rate through the corresponding selection keys 438, 440, 442,and 448 on the fly, and the controller 52 and GUI instantaneously adjustto the new parameter settings. As before mentioned, in the illustratedembodiment, the controller 52 does not permit change of thechannel/electrode while radio frequency energy is being applied, and,for this reason, the channel selection icon 458 is dimmed.

[0445] Unlike the Standby and Ready screens, the RF-On screen alsodisplays a real time line graph 468 to show changes to the temperatureprofile (Y-axis) over time (X-axis). The RF-On screen also shows arunning clock icon 470, which changes appearance to count toward thetarget duration. In the illustrated embodiment, a digital clock displayCD is also shown, indicating elapsed time.

[0446] The line graph 468 displays four trending lines to show theminimum and maximum surface and tip temperature readings from all activeelectrodes. In the illustrated embodiment, the time axis (X-axis) isscaled to one of five pre-set maximum durations, depending upon the settarget duration. For example, if the target duration is 0 to 3 minutes,the maximum time scale is 3:30 minutes. If the target duration is 3 to 6minutes, the maximum time scale is 6:30 seconds, and so on.

[0447] The line graph 468 displays two background horizontal bars HB1and HB2 of different colors. The upper bar HB1 is colored, e.g., green,and is centered to the target coagulation temperature with a spread ofplus and minus 10 degrees C. The lower bar HB2 is colored, e.g., red,and is fixed at a prescribed maximum (e.g., 40 degrees C.) to alertpotential surface overheating.

[0448] The line graph 468 also displays a triangle marker TM of aselected color (e.g., red) (see FIG. 80) with a number corresponding tothe channel/electrode that is automatically turned off by the controller52 due to operation outside the selected parameters. As beforedescribed, the circle C1 and boxes B1 and B3 for this electrode/channelare also modified in the electrode icon 466 when this situation occurs.

[0449] The Electrode Icon 466 can graphically display other types ofstatus or configuration information pertinent to the treatment deviceTD. For example, the Electrode Icon 466 can display a flashing animationin spatial relation to the idealized electrodes to constantly remind thephysician that the electrode is extended into tissue. The flashinganimation ceases to be shown when the electrode is retracted. Theflashing animation reminds the physician to retract the electrodesbefore removing the treatment device TD. As another example, theElectrode Icon 466 can display another flashing animation when theexpandable structure of the treatment device TD is expanded. Theflashing animation reminds the physician to collapse the electrodesbefore removing the treatment device TD.

[0450] (v) Pause

[0451] The controller 52 terminates the conveyance of radio frequencyablation energy to the electrodes and the RF-On screen changes into thePause screen (see FIG. 81), due to any of the following conditions (i)target duration is reached, (ii) all channels/electrodes have anerroneous coagulation condition (electrode or surface temperature orimpedance out of range), or (iii) manual termination of radio frequencyenergy application by pressing the foot pedal 416 or the Standby/ReadyButton 430.

[0452] Upon termination of radio frequency ablation energy, the runningclock icon 470 stops to indicate total elapsed time. The controller 52commands the continued supply of cooling liquid through the treatmentdevice TD into contact with mucosal tissue at the targeted site. At thesame time, cooling liquid is aspirated from the treatment device TD inan open loop. This flow of cooling liquid continues for a predeterminedtime period (e.g. 2 to 5 seconds) after the supply of radio frequencyablation energy is terminated, after which the controller 52 stops thepump rotor 428.

[0453] During Pause, the controller 52 continues to supply intermittentbursts of low power radio frequency energy to acquire impedanceinformation.

[0454] The Pause screen is in most respects similar to the RF-On screen.The Pause screen displays the Screen Icon 450, to indicate that thetreatment device TD is connected and deployed in the patient'sesophagus. The flashing radio wave animation is not present, indicatingthat radio frequency energy is no longer being applied. The RF OnIndicator 434 is, however, intermittently illuminated to indicate thatbursts of radio frequency energy are being applied by the electrodes toacquire impedance information.

[0455] The RF-On screen also updates the Electrode Icon 466 to displayin the boxes B1 and B3 the actual sensed tip temperature and impedanceconditions. However, no background color changes are registered on thePause screen, regardless of whether the sensed conditions are without oroutside the prescribed ranges.

[0456] The Pause screen continues to display the target duration icon452, target temperature icon 454, maximum power icon 456, channelselection icon 458, coagulation level icon 460, and flow rate/primingicon 462, indicating the current selected parameter values.

[0457] The real time temperature line graph 468 continues to display thefour trending lines, until the target duration is reached and fiveadditional seconds elapse, to show the drop off of electrodetemperature.

[0458] If further treatment is desired, pressing the Standby/Readybutton 430 returns the device 400 from the Pause back to the Ready mode.

[0459] (vi) Procedure Log

[0460] As previously described, the floppy disk icon 464 and coagulationlevel icon 460 are normally dimmed on the various screens, until afloppy disk is inserted in the drive 426. When a floppy disk is insertedin the drive 426, the icons 460 and 464 are illuminated, and data issaved automatically after each application of radio frequency energy.

[0461] When the floppy disk is inserted, the controller 52 downloadsdata to the disk each time it leaves the RF-On screen, either by defaultor manual termination of the procedure. The downloaded data creates aprocedure log. The log documents, by date of treatment and number oftreatments, the coagulation level, the coagulation duration, energydelivered by each electrode, and the coolant flow rate. The procedurelog also records at pre-established intervals (e.g., every 5 seconds)the temperatures of the electrode tips and surrounding tissue,impedance, and power delivered by each electrode. The procedure logpreferably records these values in a spreadsheet format.

[0462] The housing 400 can carry an integrated printer, or can becoupled through the I/O device 54 to an external printer. The printerprints a procedure log in real time, as the procedure takes place.

[0463] Various features of the invention are set forth in the followingclaims.

We claim:
 1. An assembly for treating a tissue region at or near asphincter comprising a support structure, an electrode having a firstcircumferential dimension and including a distal end configured topenetrate tissue, the electrode being carried by the support structurefor advancement in a path to penetrate a surface of the tissue region,the electrode having a non-cylindrical cross section selected to resistdeflection when advanced to penetrate the tissue region, and a limitcollar circumferentially extending about the electrode a set distancefrom the distal end, the limit collar having a second circumferentialdimension larger than the first circumferential dimension to abutagainst the surface of the tissue region penetrated by the distal endand thereby resist further advancement of the distal end in the tissueregion beyond the set distance.
 2. An assembly according to claim 1wherein the non-cylindrical cross section is rectilinear.
 3. An assemblyaccording to claim 1 wherein the non-cylindrical cross section is oval.4. An assembly according to claim 1 wherein the non-cylindrical crosssection is elliptical.
 5. An assembly according to claim 1 wherein theelectrode includes an axis, and wherein the electrode is bent along theaxis.
 6. An assembly according to claim 5 wherein the electrode is bentin an antegrade direction.
 7. An assembly according to claim 5 whereinthe electrode is bent in a retrograde direction.
 8. An assemblyaccording to claim 5 wherein the electrode is bent along the axis in anarc of less than ninety degrees.
 9. An assembly according to claim 5wherein the electrode is bent along the axis in an arc of greater thanninety degrees.
 10. An assembly according to claim 1 wherein the supportstructure expands and collapses.
 11. An assembly according to claim 1wherein the support structure includes circumferentially spaced spinesforming a basket, and wherein the electrode is carried by a spine. 12.An assembly according to claim 1 wherein at least four electrodes arecarried in a circumferential, spaced apart relationship by the supportstructure.
 13. An assembly according to claim 1 wherein eight electrodesare carried in a circumferentially spaced apart relationship by thesupport structure.
 14. An assembly according to claim 1 wherein thesupport structure is pre-shaped to conform to the tissue region.
 15. Anassembly according to claim 1 wherein the electrode includes a proximalportion formed from a first material and a distal tissue penetratingportion formed of a second material different than the first material.16. An assembly according to claim 14 wherein the electrode has an axis,and wherein the distal tissue penetration portion is bent along theaxis.
 17. An assembly according to claim 14 wherein the first materialincludes stainless steel and the second material includes nickeltitanium.
 18. An assembly according to claim 1 further including aconnector to couple the electrode to a source of radio frequency energyto ohmically heat tissue and create a lesion in the tissue region. 19.An assembly for treating a tissue region comprising a support structure,an electrode having a first circumferential dimension and including adistal end configured to penetrate tissue, the electrode being carriedby the support structure for advancement in a path to penetrate asurface of the tissue region, the electrode including a proximal portionformed from a first material and a distal tissue penetrating portionformed of a second material different than the first material, and alimit collar circumferentially extending about the electrode a setdistance from the distal end, the limit collar having a secondcircumferential dimension larger than the first circumferentialdimension to abut against the surface of the tissue region penetrated bythe distal end and thereby resist further advancement of the distal endin the tissue region beyond the set distance.
 20. An assembly accordingto claim 19 wherein the electrode has an axis, and wherein the distaltissue penetrating portion is bent along the axis.
 21. An assemblyaccording to claim 19 wherein at least four electrodes are carried in acircumferential, spaced apart relationship by the support structure. 22.An assembly according to claim 19 wherein eight electrodes are carriedin a circumferentially spaced apart relationship by the supportstructure.
 23. An assembly according to claim 19 wherein the supportstructure is pre-shaped to conform to the tissue region.
 24. An assemblyaccording to claim 19 wherein the first material includes stainlesssteel and the second material includes nickel titanium.
 25. An assemblyaccording to claim 19 further including a connector to couple theelectrode to a source of radio frequency energy to ohmically heat tissueand create a lesion in the tissue region.
 26. An assembly for treating atissue region at or near a sphincter comprising a support structure, anelectrode having a first circumferential dimension and including adistal end configured to penetrate tissue, the electrode being carriedby the support structure for advancement in a path to penetrate asurface of the tissue region, and a limit collar circumferentiallyextending about the electrode a set distance from the distal end, thelimit collar having a second circumferential dimension larger than thefirst circumferential dimension to abut against the surface of thetissue region penetrated by the distal end and thereby resist furtheradvancement of the distal end in the tissue region beyond the setdistance.
 27. An assembly according to claim 26 wherein the electrodeincludes an axis, and wherein the electrode is bent along the axis. 28.An assembly according to claim 26 wherein the support structure expandsand collapses.
 29. An assembly according to claim 26 wherein at leastfour electrodes are carried in a circumferential, spaced apartrelationship by the support structure.
 30. An assembly according toclaim 26 wherein eight electrodes are carried in a circumferentiallyspaced apart relationship by the support structure.
 31. An assemblyaccording to claim 26 wherein the support structure is pre-shaped toconform to the tissue region.
 32. An assembly according to claim 26further including a connector to couple the electrode to a source ofradio frequency energy to ohmically heat tissue and create a lesion inthe tissue region.